Mr. Justice Brennan

delivered the opinion of the Court.

The McCarran Amendment, 66 Stat. 560, 43 U. S. C. § 666, provides that “consent is hereby given to join the United States as a defendant in any suit (1) for the adjudication of rights to the use of water of a river system or other source, or (2) for the administration of such *803rights, where it appears that the United States is the owner of or is in the process of acquiring water rights by appropriation under State law, by purchase, by exchange, or otherwise, and the United States is a necessary party to such suit.” The questions presented by this case concern the effect of the McCarran Amendment upon the jurisdiction of the federal district courts under 28 U. S. C. § 1345 over suits for determination of water rights brought by the United States as trustee for certain Indian tribes and as owner of various non-Indian Government claims.1

*804I

It is probable that no problem of the Southwest section of the Nation is more critical than that of scarcity of water. As southwestern populations have grown, conflicting claims to this scarce resource have increased. To meet these claims, several Southwestern States have established elaborate procedures for allocation of water and adjudication of conflicting claims to that resource.2 In 1969, Colorado enacted its Water Rights Determination and Administration Act3 in an effort to revamp its legal procedures for determining claims to water within the State.

Under the Colorado Act, the State is divided into seven Water Divisions, each Division encompassing one or more entire drainage basins for the larger rivers in Colorado.4 Adjudication of water claims within each Division occurs on a continuous basis.5 . Each month, Water Referees in each Division rule on applications for water rights filed within the preceding five months or refer those applications to the Water Judge of their Division.6 Every six months, the Water Judge passes on referred applications and contested decisions by Referees.7 A State Engineer and engineers for each Division are responsible for the administration and dis*805tribution of the waters of the State according to the determinations in each Division.8

Colorado applies the doctrine of prior appropriation in establishing rights to the use of water.9 Under that doctrine, one acquires a right to water by diverting it from its natural source and applying it to some beneficial use. Continued beneficial use of the water is required in order to maintain the right. In periods of shortage, priority among confirmed rights is determined according to the date of initial diversion.10

The reserved rights of the United States extend to Indian reservations, Winters v. United States, 207 U. S. 564 (1908), and other federal lands, such as national parks and forests, Arizona v. California, 373 U. S. 546 (1963). The reserved rights claimed by the United States in this case affect waters within Colorado Water Division No. 7. On November 14, 1972, the Government instituted this suit in the United States District Court for the District of Colorado, invoking the court’s jurisdiction under 28 U. S. C. § 1345. The District Court is located in Denver, some 300 miles from Division 7. The suit, against some 1,000 water users, sought declaration of the Government’s rights to waters in certain rivers and their tributaries located in Division 7. In the suit, the Government asserted reserved rights on its own behalf and on behalf of certain Indian tribes, as well as rights based on state law. It sought appointment of a water master to administer any waters decreed to the United States. *806Prior to institution of this suit, the Government had pursued adjudication of non-Indian reserved rights and other water claims based on state law in Water Divisions 4, 5, and 6, and the Government continues to participate fully in those Divisions.

Shortly after the federal suit was commenced, one of the defendants in that suit filed an application in the state court for Division 7, seeking an order directing service of process on the United States in order to make it a party to proceedings in Division 7 for the purpose of adjudicating all of the Government’s claims, both state and federal. On January 3, 1973, the United States was served pursuant to authority of thé McCarran Amendment. Several defendants and intervenors in the federal proceeding then filed a motion in the District Court to dismiss on the ground that under the Amendment, the court was without jurisdiction to determine federal water rights. Without deciding the jurisdictional question, the District Court, on June 21, 1973, granted the motion in an unreported oral opinion stating that the doctrine of abstention required deference to the proceedings in Division 7. On appeal, the Court of Appeals for the Tenth Circuit reversed, United States v. Akin, 504 F. 2d 115 (1974), holding that the suit of the United States was within district-court jurisdiction under 28 U. S. C. § 1345, and that abstention was inappropriate. We granted certiorari to consider the important questions of whether the McCarran Amendment terminated jurisdiction of federal courts to adjudicate federal water rights and whether, if that jurisdiction was not terminated, the District Court’s dismissal in this case was nevertheless appropriate. 421 U. S. 946 (1975). We reverse.

II

We first consider the question of district-court jurisdiction under 28 U. S. C. § 1345. That section provides *807that the district courts shall have original jurisdiction over all civil actions brought by the Federal Government “[ejxcept as otherwise provided by Act of Congress.” It is thus necessary to examine whether the McCarran Amendment is such an Act of Congress excepting jurisdiction under § 1345.

The McCarran Amendment does not by its terms, at least, indicate any repeal of jurisdiction under § 1345. Indeed, subsection (d) of the Amendment, which is un-codified, provides:

“(d) None of the funds appropriated by this title may be used in the preparation or prosecution of the suit in the United States District Court for the Southern District of California, Southern Division, by the United States of America against Fallbrook Public Utility District, a public service corporation of the State of California, and others.” Act of July 10, 1952, Pub. L. 495, § 208 (d), 66 Stat. 560.

In prohibiting the use of funds for the maintenance by the United States of a specific suit then pending in a District Court, subsection (d) plainly implies that the Amendment did not repeal the jurisdiction of district courts under § 1345 to adjudicate suits brought by the United States for adjudication of claimed federal water rights.11

Beyond its terms, the legislative history of the Amendment evidences no clear purpose to terminate any portion of i 1345 jurisdiction. Indeed, three bills, proposed at approximately the same time as the Amendment, which expressly would have had the effect of precluding suits by the United States in district court for the determina*808tion of water rights, failed of passage.12 Further, the Senate report on the Amendment states: “The purpose of the proposed legislation, as amended, is to permit the joinder of the United States as a party defendant in any suit for the adjudicátion of rights to the use of water_” 13 Nothing in this statement of purpose indicates an intent correlatively to diminish federal-district-court jurisdiction. Similarly, Senator McCarran, who introduced the legislation in the Senate, stated in a letter made a part of the Senate report that the legislation was “not intended to be used for any other purpose than to allow the United States to be joined in a suit wherein it is necessary to adjudicate all of the rights of various owners on a given stream.” 14

In view of the McCarran Amendment’s language and legislative history, controlling principles of statutory construction require the conclusion that the Amendment did not constitute an exception “provided by Act of Congress” that repealed the jurisdiction of district courts under § 1345 to entertain federal water suits. “When there are statutes clearly defining the jurisdiction of the courts the force and effect of such provisions should not be disturbed by a mere implication flowing from subsequent legislation.” Rosencrans v. United States, 165 U. S. 257, 262 (1897). See Morton v. Mancari, 417 U. S. 535, 549-551 (1974); United States v. Jackson, 302 U. S. 628, 632 (1938). “In the absence of some . affirmative showing of an intention to repeal, the only permissible justification for a repeal by implication is when the earlier and later statutes are irreconcilable.” Morton v. Mancari, supra, at 550. Not only do the terms and legislative *809history of the McCarran Amendment not indicate an intent to repeal § 1345, but also there is no irreconcilability in the operation of both statutes. The immediate effect of the Amendment is to give consent to jurisdiction in the state courts concurrent with jurisdiction in the federal courts over controversies involving federal rights to the use of water. There is no irreconcilability in the existence of concurrent state and federal jurisdiction. Such concurrency has, for example, long existed under federal diversity jurisdiction. Accordingly, we hold that the Mc-Carran Amendment in no way diminished federal-district-court jurisdiction under § 1345 and that the District Court had jurisdiction to hear this case.15

Ill

We turn next to the question whether this suit nevertheless was properly dismissed in view of the concurrent state proceedings in Division 7.

A

First, we consider whether the McCarran Amendment provided consent to determine federal reserved rights held on behalf of Indians in state court. This is a question not previously squarely addressed by this Court, and given the claims for Indian water rights in this case, dismissal clearly would have been inappropriate if the state court had no jurisdiction to decide those claims. We conclude that the state court had jurisdiction over Indian water rights under the Amendment.

United States v. District Court for Eagle County, 401 U. S. 520 (1971), and United States v. District Court for *810 Water Div. 5, 401 U. S. 527 (1971), held that the provisions of the McCarran Amendment, whereby “consent is . . . given to join the United States as a defendant in any suit (1) for the adjudication ... or (2) for the administration of [water] rights, where it appears that the United States is the owner ... by appropriation under state law, by purchase, by exchange, or otherwise . . . subject federal reserved rights to general adjudication in state proceedings for the determination of water rights. More specifically, the Court held that reserved rights were included in those rights where the United States was “otherwise” the owner. United States v. District Court for Eagle County, supra, at 524. Though Eagle County and Water Div. 5 did not involve reserved rights on Indian reservations, viewing the Government’s trusteeship of Indian rights as ownership, the logic of those cases clearly extends to such rights. Indeed, Eagle County spoke of non-Indian rights and Indian rights without any suggestion that there was a distinction between them for purposes of the Amendment. 401 U. S., at 523.

Not only the Amendment’s language, but also its underlying policy, dictates a construction including Indian rights in its provisions. Eagle County rejected the conclusion that federal reserved rights in general were not reached by the Amendment for the reason that the Amendment “[deals] with an all-inclusive statute concerning ‘the adjudication of rights to the use of water of a river system.’ ” Id., at 524. This consideration applies as well to federal water rights reserved for Indian reservations. And cogently, the Senate report on the Amendment observed:

“In the administration of and the adjudication ol water rights under State laws the State courts are vested with the jurisdiction necessary for the propel' *811and efficient disposition thereof, and by reason of the interlocking of adjudicated rights on any stream system, any order or action affecting one right affects all such rights. Accordingly all water users on a stream, in practically every case, are interested and necessary parties to any court proceedings. It is apparent that if any water user claiming to hold such right by reason of the ownership thereof by the United States or any of its departments is permitted to claim immunity from suit in, or orders of, a State court, such claims could materially interfere with the lawful and equitable use of water for beneficial use by the other water users who are amenable to and bound by the decrees and orders of the State courts.” 16

Thus, bearing in mind the ubiquitous nature of Indian water rights in the Southwest, it is clear that a construction of the Amendment excluding those rights from its coverage would enervate the Amendment’s objective.17

Finally, legislative history demonstrates that the McCarran Amendment is to be construed as reaching federal water rights reserved on behalf of Indians. It was unmistakably the understanding of proponents and opponents of the legislation that it comprehended water rights reserved for Indians. In the Senate hearings on the Amendment, participants for the Department of Justice and the Department of the Interior made clear that the proposal would include water rights reserved on behalf of *812Indians.18 In addition, the Senate report on the Amendment took note of a recommendation in a Department of the Interior report that no consent to suit be given as to Indian rights and rejected the recommendation.19

The Government argues that because of its fiduciary responsibility to protect Indian rights, any state-court jurisdiction over Indian property should not be recognized unless expressly conferred by Congress. It has been recognized, however, that an action for the destruction of personal property may be brought against an Indian tribe where “[a]uthority to sue ... is implied.” Turner v. United States, 248 U. S. 364, 358 (1919). Moreover, the Government's argument rests on the incorrect assumption that consent to state jurisdiction for the purpose of determining water rights imperils those rights or in some way breaches the special obligation of the Federal Government to protect Indians. Mere subjection of Indian rights to legal challenge in state court, however, would no more imperil those rights than would a suit brought by the Government in district court for their declaration, a suit which, absent the consent of the Amendment, would eventually be necessitated to resolve conflicting claims to a scarce resource. The Government has not abdicated any responsibility fully to defend Indian rights in state court, and Indian interests may be satisfactorily protected under regimes of state law. See 25 U. S. C. §§ 1321, 1322 ; 28 U. S. C. § 1360.20 Cf. *813 California Oregon Power Co. v. Beaver Portland Cement Co., 295 U. S. 142, 164 n. 2 (1935). The Amendment in no way abridges any substantive claim on behalf of Indians under the doctrine of reserved rights. Moreover, as Eagle County said, “questions [arising from the collision of private rights and reserved rights of the United States], including the volume and scope of particular reserved rights, are federal questions which, if preserved, can be reviewed [by the Supreme Court] after final judgment by the Colorado court.” 401 U. S., at 526.

B

Next, we consider whether the District Court’s dismissal was appropriate under the doctrine of abstention. We hold that the dismissal cannot be supported under that doctrine in any of its forms.

Abstention from the exercise of federal jurisdiction is the exception, not the rule. “The doctrine of abstention, under which a District Court may decline to exercise or postpone the exercise of its jurisdiction, is an extraordinary and narrow exception to the duty of a District Court to adjudicate a controversy properly before it. Abdication of the obligation to decide cases can be justified under this doctrine only in the exceptional circumstances where the order to the parties to repair to the State court would clearly serve an important countervailing interest.” County of Allegheny v. Frank Mashuda Co., 360 U. S. 185, 188-189 (1959). “[I]t was *814never a doctrine of equity that a federal court should exercise its judicial discretion to dismiss a suit merely because a State court could entertain it.” Alabama Pub. Serv. Comm’n v. Southern R. Co., 341 U. S. 341, 361 (1951) (Frankfurter, J., concurring in result). Our decisions have confined the circumstances appropriate for abstention to three general categories.

(a) Abstention is appropriate “in cases presenting a federal constitutional issue which might be mooted or presented in a different posture by a state court determination of pertinent state law.” County of Allegheny v. Frank Mashuda Co., supra, at 189. See, e. g., Lake Carriers Assn. v. MacMullan, 406 U. S. 498 (1972); United Gas Pipeline Co. v. Ideal Cement Co., 369 U. S. 134 (1962); Railroad Comm’n of Texas v. Pullman Co., 312 U. S. 496 (1941). This case, however, presents no federal constitutional issue for decision.

(b) Abstention is also appropriate where there have been presented difficult questions of state law bearing on policy problems of substantial public import whose importance transcends the result in the case then at bar. Louisiana Power & Light Co. v. City of Thibodaux, 360 U. S. 25 (1959), for example, involved such a question. In particular, the concern there was with the scope of the eminent domain power of municipalities under state law. See also Kaiser Steel Corp. v. W. S. Ranch Co., 391 U. S. 593 (1968); Hawks v. Hamill, 288 U. S. 52 (1933). In some cases, however, the state question itself need not be determinative of state policy. It is enough that exercise of federal review of the question in a case and in similar cases would be disruptive of state efforts to establish a coherent policy with respect to a matter of substantial public concern. In Burford v. Sun Oil Co., 319 U. S. 315 (1943), for example, the Court held that a suit seeking review of the reasonableness under Texas state law of a state commission’s permit to drill oil *815wells should have been dismissed by the District Court. The reasonableness of the permit in that case was not of transcendent importance, but review of reasonableness by the federal courts in that and future cases, where the State had established its own elaborate review system for dealing with the geological complexities of oil and gas fields, would have had an impermissibly disruptive effect on state policy for the management of those fields. See also Alabama Pub. Serv. Comm’n v. Southern R. Co., supra. 21

The present case clearly does not fall within this second category of abstention. While state claims are involved in the case, the state law to be applied appears to be settled. No questions bearing on state policy are presented for decision. Nor will decision of the state claims impair efforts to implement state policy as in Burford. To be sure, the federal claims that are in*816volved in the case go to the establishment of water rights which may conflict with similar rights based on state law. But the mere potential for conflict in the results of adjudications, does not, without more, warrant staying exercise of federal jurisdiction. See Meredith v. Winter Haven, 320 U. S. 228 (1943); Kline v. Burke Constr. Co., 260 U. S. 226 (1922); McClellan v. Carland, 217 U. S. 268 (1910). The potential conflict here, involving state claims and federal claims, would not be such as to impair impermissibly the State’s effort to effect its policy respecting the allocation of state waters. Nor would exercise of federal jurisdiction here interrupt any such efforts by restraining the exercise of authority vested in state officers. See Pennsylvania v. Williams, 294 U. S. 176 (1935); Hawks v. Hamill, supra.

(c) Finally, abstention is appropriate where, absent bad faith, harassment, or a patently invalid state statute, federal jurisdiction has been invoked for the purpose of restraining state criminal proceedings, Younger v. Harris, 401 U. S. 37 (1971); Douglas v. City of Jeannette, 319 U. S. 157 (1943);22 state nuisance proceedings antecedent to a criminal prosecution, which are directed at obtaining the closure of places exhibiting obscene films, Huffman v. Pursue, Ltd., 420 U. S. 592 (1975); or collection of state taxes, Great Lakes Dredge & Dock Co. v. Huffman, 319 U. S. 293 (1943). Like the previous two categories, this category also does not include this case. We deal here neither with a criminal proceeding, nor such a nuisance proceeding, nor a tax collection. We also do not deal with an attempt to restrain such actions 23 or to seek a *817declaratory judgment as to the validity of a state criminal law under which criminal proceedings are pending in a state court.

C

Although this case falls within none of the abstention categories, there are principles unrelated to considerations of proper constitutional adjudication and regard for federal-state relations which govern in situations involving the contemporaneous exercise of concurrent jurisdictions, either by federal courts or by state and federal courts. These principles rest on considerations of “[w]ise judicial administration, giving regard to conservation of judicial resources and comprehensive disposition of litigation.” Kerotest Mfg. Co. v. C-O-Two Fire Equipment Co., 342 U. S. 180, 183 (1952). See Columbia Plaza Corp. v. Security National Bank, 173 U. S. App. D. C. 403, 525 F. 2d 620 (1975). Generally, as between state and federal courts, the rule is that “the pendency of an action in the state court is no bar to proceedings concerning the same matter in the Federal court having jurisdiction . . . .” McClellan v. Garland, supra, at 282. See Donovan v. City of Dallas, 377 U. S. 408 (1964). As between federal district courts, however, though no precise rule has evolved, the general principle is to avoid duplicative litigation. See Kerotest Mfg. Co. v. C-O-Two Fire Equipment Co., supra; Steelman v. All Continent Corp., 301 U. S. 278 (1937); Landis v. North American Co., 299 U. S. 248, 254 (1936). This difference in general approach between state-federal concurrent jurisdiction and wholly federal concurrent jurisdiction stems from the virtually unflagging obligation of the federal courts to exercise the jurisdiction given them. England v. Medical Examiners, 375 U. S. 411, *818415 (1964); McClellan v. Carland, supra, at 281; Cokens v. Virginia, 6 Wheat. 264, 404 (1821) (dictum). Given this obligation, and the absence of weightier considerations of constitutional adjudication and state-federal relations, the circumstances permitting the dismissal of a federal suit due to the presence of a concurrent state proceeding for reasons of wise judicial administration are considerably more limited than the circumstances appropriate for abstention. The former circumstances, though exceptional, do nevertheless exist.

It has been held, for example, that the court first assuming jurisdiction over property may exercise that jurisdiction to the exclusion of other courts. Donovan v. City of Dallas, supra, at 412; Princess Lida v. Thompson, 305 U. S. 456, 466 (1939); United States v. Bank of New York Co., 296 U. S. 463, 477 (1936). But cf. Markham v. Allen, 326 U. S. 490 (1946); United States v. Klein, 303 U. S. 276 (1938). This has been true even where the Government was a claimant in existing state proceedings and then sought to invoke district-court jurisdiction under the jurisdictional provision antecedent to 28 U. S. C. § 1345. United States v. Bank of New York Co., supra, at 479. But cf. Leiter Minerals, Inc. v. United States, 352 U. S. 220, 227-228 (1957). In assessing the appropriateness of dismissal in the event of an exercise of concurrent jurisdiction, a federal court may also consider such factors as the inconvenience of the federal forum, cf. Gulf Oil Corp. v. Gilbert, 330 U. S. 501 (1947); the desirability of avoiding piecemeal litigation, cf. Brillhart v. Excess Ins. Co., 316 U. S. 491, 495 (1942); and the order in which jurisdiction was obtained by the concurrent forums, Pacific Live Stock Co. v. Oregon Water Bd., 241 U. S. 440, 447 (1916). No one factor is necessarily determinative; a carefully considered judgment taking into account both the obligation to exercise jurisdiction and the combination of factors counselling against that exer*819cise is required. See Landis v. North American Co., supra, at 254-255. Only the clearest of justifications will warrant dismissal.

Turning to the present case, a number of factors clearly counsel against concurrent federal proceedings. The most important of these is the McCarran Amendment itself. The clear federal policy evinced by that legislation is the avoidance of piecemeal adjudication of water rights in a river system. This policy is akin to that underlying the rule requiring that jurisdiction be yielded to the court first acquiring control of property, for the concern in such instances is with avoiding the generation of additional litigation through permitting inconsistent dispositions of property. This concern is heightened with respect to water rights, the relationships among which are highly interdependent. Indeed, we have recognized that actions seeking the allocation of water essentially involve the disposition of property and are best conducted in unified proceedings. See Pacific Live Stock Co. v. Oregon Water Bd., supra, at 449. The consent to jurisdiction given by the McCarran Amendment bespeaks a policy that recognizes the availability of comprehensive state systems for adjudication of water rights as the means for achieving these goals.

As has already been observed, the Colorado Water Rights Determination and Administration Act established such a system for the adjudication and management of rights to the use of the State’s waters. As the Government concedes24 and as this Court recognized in Eagle County and Water Div. 5, the Act established a single continuous proceeding for water rights adjudication which antedated the suit in District Court. United States v. District Court for Eagle County, 401 U. S., at 525; United States v. District Court for Water Div. 5, *820401 U. S., at 529. That proceeding “reaches all claims, perhaps month by month but inclusively in the totality.” Ibid. Additionally, the responsibility of managing the State’s waters, to the end that they be allocated in accordance with adjudicated water rights, is given to the State Engineer.

Beyond the congressional policy expressed by the Mc-Carran Amendment and consistent with furtherance of that policy, we also find significant (a) the apparent absence of any proceedings in the District Court, other than the filing of the complaint, prior to the motion to dismiss,25 (b) the extensive involvement of state water rights occasioned by this suit naming 1,000 defendants, (c) the 300-mile distance between the District Court in Denver and the court in Division 7, and (d) the existing participation by the Government in Division 4, 5, and 6 proceedings. We emphasize, however, that we do not overlook the heavy obligation to exercise jurisdiction. We need not decide, for example, whether, despite the McCarran Amendment, dismissal would be warranted if more extensive proceedings had occurred in the District Court prior to dismissal, if the involvement of state water rights were less extensive than it is here, or if the state proceeding were in some respect inadequate to resolve the federal claims. But the opposing factors here, particularly the policy underlying the McCarran Amendment, justify the District Court’s dismissal in this particular case.26

*821The judgment of the Court of Appeals is reversed and the judgment of the District Court dismissing the complaint is affirmed for the reasons here stated.

It is so ordered.

Mr. Justice Stewart,

with whom Mr. Justice Black-mun and Mr. Justice Stevens concur, dissenting.

The Court says that the United States District Court for the District of Colorado clearly had jurisdiction over this lawsuit. I agree.1 The Court further says that the McCarran Amendment “in no way diminished” the District Court’s jurisdiction. I agree.2 The Court also says that federal courts have a “virtually unflagging obligation ... to exercise the jurisdiction given them.” I agree.3 And finally, the Court says that nothing in the abstention doctrine “in any of its forms” justified the District Court’s dismissal of the Government’s complaint. I agree.4 These views would seem to lead ineluctably to the conclusion that the District Court was wrong in dismissing the complaint. Yet the Court holds that the order of dismissal was “appropriate.” With that conclusion I must respectfully disagree.

*822In holding that the United States shall not be allowed to proceed with its lawsuit, the Court relies principally on cases reflecting the rule that where “control of the property which is the subject of the suit [is necessary] in order to proceed with the cause and to grant the relief sought, the jurisdiction of one court must of necessity yield to that of the other.” Penn General Casualty Co. v. Pennsylvania ex rel. Schnader, 294 U. S. 189, 195. See also Donovan v. City of Dallas, 377 U. S. 408; Princess Lida v. Thompson, 305 U. S. 456; United States v. Bank of New York Co., 296 U. S. 463. But, as those cases make clear, this rule applies only when exclusive control over the subject matter is necessary to effectuate a court’s judgment. 1A J. Moore, Federal Practice ¶ 0.214 (1974). Here the federal court did not need to obtain in rem or. quasi in rem jurisdiction in order to decide the issues before it. The court was asked simply to determine as a matter of federal law whether federal reservations of water rights had occurred, and, if so, the date and scope of the reservations. The District Court could make such a determination without having control of the river.

The rule invoked by the Court thus does not support the conclusion that it reaches. In the Princess Lida case, for example, the reason for the surrender of federal jurisdiction over the administration of a trust was the fact that a state court had already assumed jurisdiction over the trust estate. But the Court in that case recognized that this rationale “ha[d] no application to a case in a federal court... wherein the plaintiff seeks merely an adjudication of his right or his interest as a basis of a claim against a fund in the possession of a state court . . . .” 305 U. S., at 466. The Court stressed that “[n]o question is presented in the federal court as to the right of any person to participate in the res or as to the quantum of his interest in it.” Id., at 467. Similarly, in the *823 Bank of New York case, supra, the Court stressed that the “object of the suits is to take the property from the depositaries and from the control of the state court, and to vest the property in the United States . . . 296 U. S., at 478. “The suits are not merely to establish a debt or a right to share in property, and thus to obtain an adjudication which might be had without disturbing the control of the state court.” Ibid. 5 See also Markham v. Allen, 326 U. S. 490; United States v. Klein, 303 U. S. 276. See generally 1A J. Moore, Federal Practice ¶ 0.222 (1974); 14 C. Wright, A. Miller, & E. Cooper, Federal Practice & Procedure §3631, pp. 19-22 (1976).

The precedents cited by the Court thus not only fail to support the Court’s decision in this case, but expressly point in the opposite direction. The present suit, in short, is not analogous to the administration of a trust, but rather to a claim of a “right to participate,” since the United States in this litigation does not ask the court to control the administration of the river, but only to determine its specific rights in the flow of water in the river. This is an almost exact analogue to a suit seeking a determination of rights in the flow of income from a trust.

The Court’s principal reason for deciding to close the doors of the federal courthouse to the United States in this case seems to stem from the view that its decision will avoid piecemeal adjudication of water rights.6 To *824the extent that this view is based on the special considerations governing in rem proceedings, it is without precedential basis, as the decisions discussed above demonstrate. To the extent that the Court’s view is based on the realistic practicalities of this, case, it is simply wrong, because the relegation of the Government to the state courts will not avoid piecemeal litigation.

The Colorado courts are currently engaged in two types of proceedings under the State’s water-rights law. First, they are processing new claims to water based on recent appropriations. Second, they are integrating these new awards of water rights with all past decisions awarding such rights into one all-inclusive tabulation for each water source. The claims of the United States that are involved in this case have not been adjudicated in the past. Yet they do not involve recent appropriations of water. In fact, these claims are wholly dissimilar to normal state water claims, because they are not *825based on actual beneficial use of water but rather on an intention formed at the time the federal land use was established to reserve a certain amount of water to support the federal reservations. The state court will, therefore, have to conduct separate proceedings to determine these claims. And only after the state court adjudicates the claims will they be incorporated into the water source tabulations. If this suit were allowed to proceed in federal court the same procedures would be followed, and the federal court decree would be incorporated into the state tabulation, as other federal court decrees have been incorporated in the past. Thus, the same process will occur regardless of which forum considers these claims. Whether the virtually identical separate proceedings take place in a federal court or a state court, the adjudication of the claims will be neither more nor less “piecemeal.” Essentially the same process will be followed in each instance.7

As the Court says, it is the virtual “unflagging obligation” of a federal court to exercise the jurisdiction that has been conferred upon it. Obedience to that obligation is particularly “appropriate” in this case, for at least two reasons.

First, the issues involved are issues of federal law. A federal court is more likely than a state court to be familiar with federal water law and to have had experience in interpreting the relevant federal statutes, regulations, *826and Indian treaties. Moreover, if tried in a federal court, these issues of federal law will be reviewable in a federal appellate court, whereas federal judicial review of the state courts’ resolution of issues of federal law will be possible only on review by this Court in the exercise of its certiorari jurisdiction.

Second, some of the federal claims in this lawsuit relate to water reserved for Indian reservations. It is not necessary to determine that there is no state-court jurisdiction of these claims to support the proposition that a federal court is a more appropriate forum than a state court for determination of questions of life-and-death importance to Indians. This Court has long recognized that “ '[t]he policy of leaving Indians free from state jurisdiction and control is deeply rooted in the Nation’s history.’ ” McClanahan v. Arizona State Tax Comm’n, 411 U. S. 164, 168, quoting Rice v. Olson, 324 U. S. 786, 789.

The Court says that “[o]nly the clearest of justifications will warrant dismissal” of a lawsuit within the jurisdiction of a federal court. In my opinion there was no justification at all for the District Court’s order of dismissal in this case.

I would affirm the judgment of the Court of Appeals.

Mr. Justice Stevens,

dissenting.

While I join Mr. Justice Stewart’s dissenting opinion, I add three brief comments:

First, I find the holding that the United States may not litigate a federal claim in a federal court having jurisdiction thereof particularly anomalous. I could not join such a disposition unless commanded to do so by an unambiguous statutory mandate or by some other clearly identifiable and applicable rule of law. The McCarran Amendment to the Department of Justice Appropriation *827Act of 1953, 66 Stat. 560, 43 U. S. C. § 666, announces no such rule.

Second, the Federal Government surely has no lesser right of access to the federal forum than does a private litigant, such as an Indian asserting his own claim. If this be so, today’s holding will necessarily restrict the access to federal court of private plaintiffs asserting water rights claims in Colorado. This is a rather surprising byproduct of the MeCarran Amendment; for there is no basis for concluding that Congress intended that Amendment to impair the private citizen’s right to assert a federal claim in a federal court.

Third, even on the Court’s assumption that this case should be decided by balancing the factors weighing for and against the exercise of federal jurisdiction, I believe we should defer to the judgment of the Court of Appeals rather than evaluate those factors in the first instance ourselves. In this case the District Court erroneously dismissed the complaint on abstention grounds and the Court of Appeals found no reason why the litigation should not go forward in a federal court. Facts such as the number of parties, the distance between the courthouse and the water in dispute, and the character of the Colorado proceedings are matters which the Court of Appeals sitting in Denver is just as able to evaluate as are we.

Although I agree with Parts I, II, III-A, and III-B of the opinion of the Court, I respectfully dissent from the decision to reverse the judgment of the Court of Appeals for the Tenth Circuit.

*684FLAUM, Chief Judge.

In this case we are asked to consider how the Colorado River abstention doctrine applies to a derivative shareholder suit brought in federal court that involves the same factual predicate, most of the same defendants, and fundamentally the same legal issues as a derivative shareholder suit brought by a different plaintiff shareholder in New York state court. Pursuant to Colorado River, the district court stayed this action in favor of the state proceeding. For the reasons stated in this opinion, we conclude that the district court did not abuse its discretion in granting the stay.

I. Background

In 2000, Sears, one of the largest retailers of merchandise and services in the world, expanded its existing credit business by issuing MasterCards to individuals holding credit accounts with Sears. Sears’ credit operations had traditionally revolved around the “Sears Card,” issued to Sears customers for use in Sears stores. Faced with declining sales and an increasingly crowded retail market, Sears entered the MasterCard market to help increase revenue and earnings growth. After experiencing some initial success in the MasterCard market, in October 2002, Sears announced that its credit business was negatively impacting the company’s financials. Following this announcement, Sears’ stock price declined significantly.

A number of lawsuits ensued, including four derivative shareholder suits filed on Sears’ behalf. The first, Brewster v. Lacy, et al., 02/603873, was filed October 23, 2002, in the Supreme Court of the State of New York {“Brewster”). This matter, Clark v. Lacy, et al., was filed on November 5, 2002, in the Northern District of Illinois {“Clark ”). Additionally, two separate derivative suits were filed in the Circuit Court of Cook County. Both of those cases were consolidated before the same judge and have been stayed in favor of the New York litigation.

At issue in this appeal are the similarities between the Brewster and Clark actions. On behalf of Sears, the Brewster complaint alleges that certain officers and directors of Sears breached their fiduciary duties under New York state law in connection with Sears’ decision to enter the competitive MasterCard market. The Brewster complaint seeks damages on behalf of Sears from Sears officers and/or directors. Also premised on New York law, the Clark complaint alleges that officers and/or directors of Sears breached their fiduciary duties with respect to Sears’ MasterCard operations and seeks damages and equitable relief on behalf of Sears. The Clark complaint names four defendants not named in the Brewster lawsuit and states three additional causes of action — abuse of control, gross mismanagement, and waste of corporate assets. The defendants moved to dismiss both Brewster and Clark for failure to make demand on the board of directors as required by New York law and because the claims are barred by Sears’ charter. On June 23, 2004, the New York court issued its opinion dismissing Brewster on the grounds that the derivative plaintiff failed to make pre-suit demand on Sears’ board of directors. The time for appeal is thirty days. See N.Y. C.P.L.R. § 5513(a).

Additionally, the Clark defendants filed a motion in the district court to stay this action pursuant to the doctrine set forth in Colorado River Water Conservation District v. United States, 424 U.S. 800, 96 S.Ct. 1236, 47 L.Ed.2d 483 (1976), or in the alternative to dismiss. Based on a review of the parties’ briefs and exhibits, the district court found that the differences between the Brewster and Clark actions were *685more superficial than substantive. Using the Colorado River factors, the district court determined that a stay was warranted in this case because it would promote judicial administration. On order of the district court, the Clark action is stayed until final disposition of the New York proceedings. Clark now appeals. For the reasons discussed in this opinion, we affirm the district court’s order.

II. Analysis

We review a district court’s ruling on a motion to stay under the Colorado River doctrine for an abuse of discretion. Sverdrup Corp. v. Edwardsville Community Unit Sch. Disk No. 7, 125 F.3d 546, 550 (7th Cir.1997). Under the Colorado River abstention doctrine, a federal court may stay a suit in exceptional circumstances when there is a concurrent state proceeding and the stay would promote “wise judicial administration.” Colorado River, 424 U.S. at 818, 96 S.Ct. 1236. While recognizing the availability of judicial abstention in “exceptional circumstances,” the Court also cautioned that federal courts have a “virtually unflagging obligation ... to exercise the jurisdiction given to them.” Id. at 817-18, 96 S.Ct. 1236. Reiterating this admonition, the Court stated in Moses H. Cone Memorial Hospital v. Mercury Construction Corp., 460 U.S. 1, 25, 103 S.Ct. 927, 74 L.Ed.2d 765 (1983): “[W]e emphasize that our task in cases such as this is not to find some substantial reason for the exercise of federal jurisdiction by the district court; rather, the task is to ascertain whether there exist ‘exceptional’ circumstances, the ‘clearest of justifications,’ that can suffice under Colorado River to justify the surrender of that jurisdiction.” (emphasis in original). Given this clear command, “we treat as paramount the overriding rule that abstention is the exception.” Sverdrup, 125 F.3d at 550. Indeed, “the mere fact that an action is pending in state court is ordinarily no bar to parallel federal proceedings.” LaDuke v. Burlington N. R.R. Co., 879 F.2d 1556, 1558 (7th Cir.1989).

To determine whether a stay is appropriate in a particular case, a court must conduct a two-part analysis. First, the court must consider “whether the concurrent state and federal actions are actually parallel.” Id. at 1559, see also Interstate Material Corp. v. City of Chicago, 847 F.2d 1285, 1287 (7th Cir.1988). Then, once it is established that the suits are parallel, the court must consider a number of nonexclusive factors that might demonstrate the existence of “exceptional circumstances.” See LaDuke, 879 F.2d at 1559. These factors are: (1) whether the state has assumed jurisdiction over property; (2) the inconvenience of the federal forum; (3) the desirability of avoiding piecemeal litigation; (4) the order in which jurisdiction was obtained by the concurrent forums; (5) the source of governing law, state or federal; (6) the adequacy of state-court action to protect the federal plaintiffs rights; (7) the relative progress of state and federal proceedings; (8) the presence or absence of concurrent jurisdiction; (9) the availability of removal; and (10) the vexatious or contrived nature of the federal claim. See id. (citing Lumen Constr., Inc. v. Brant Constr. Co., 780 F.2d 691, 694-95 (7th Cir.1985)).

A. Parallel Actions

Clark contends that the district court abused its discretion by finding that the Brewster and Clark actions are parallel. According to Clark, that finding was improper because the parties and the issues in this case are more numerous and diverse than in the Brewster action. Moreover, Clark argues that the relief sought in the two actions is different. The Breiuster *686action seeks only monetary relief while the Clark action requests equitable relief in addition to money damages.

To meet the “parallel” requirement, suits need not be identical. See Interstate Material Corp., 847 F.2d at 1288. Two suits are considered “ ‘parallel’ when substantially the same parties are contemporaneously litigating substantially the same issues in another forum.” Id. (quoting Calvert Fire Insurance Co. v. American Mutual Reinsurance Co., 600 F.2d 1228, 1229 n. 1 (7th Cir.1979)). To be sufficiently similar it is not necessary that there be “formal symmetry between the two actions.” Lumen, 780 F.2d at 695. Rather, there should be a “substantial likelihood that the state litigation will dispose of all claims presented in the federal case.” Id.

After reviewing the two complaints, we agree with the district court that no meaningful distinction can be made between the Clark and Brewster lawsuits. First and foremost, although some of the names appearing on the two complaints are different, the parties’ interests in the disputes are nearly identical. Parties with “nearly identical” interests are considered “substantially the same” for Colorado River purposes. See Caminiti & Iatarola v. Behnke Warehousing, Inc., 962 F.2d 698, 700-01 (7th Cir.1992) (finding an estate and a business to be substantially the same parties in disputes involving legal fees owed by the business where the estate owned one-fourth of the business). As Brewster and Clark are derivative shareholder suits, Sears is the true party in interest in both cases. As such, we consider only Sears’ interests, not the individual interests of the plaintiffs who brought the actions on Sears’ behalf. Clark has not presented us with any reason why Sears’ own interests would diverge in these two lawsuits.

Nor does the presence of the four additional defendants in Clark render these lawsuits non-parallel. The addition of a party or parties to a proceeding, by itself, does not destroy the parallel nature of state and federal proceedings. See Schneider Nat’l Carriers, Inc. v. Carr, 903 F.2d 1154, 1156 (7th Cir.1990) (finding cases parallel where plaintiff named additional defendants in state action). Again, the requirement is that the parties be substantially the same — not completely identical. When we focus on the parties’ litigation interests in these two lawsuits, it is clear that the addition of these four defendants has little impact on the overall similarity of the disputes. As with the other defendants, the four additional defendants have been sued collectively in their capacity as Sears officers and no individualized allegations have been made against any of them. Their inclusion in the federal proceeding does not alter the case’s central issue (the same one presented by the Brewster action), i.e., whether Sears officers and/or directors breached their fiduciary duties to Sears in connection with Sears’ entry into the MasterCard market.

Clark’s argument relating to the additional claims presented in her complaint is equally unavailing. Each “additional” claim (abuse of control, gross mismanagement, and waste of corporate assets) is premised on the defendants’ alleged breach of their fiduciary duties. Cf. Amfesco Industries, Inc. v. Greenblatt, 172 A.D.2d 261, 568 N.Y.S.2d 593, 596-97 (N.Y.App.Div.1991) (categorizing claims of waste and mismanagement of corporate assets as breaches of fiduciary duty). Clark has not presented any authority that casts doubt on the likelihood that in resolving the fiduciary duty issue, the state litigation will dispose of all claims presented in this case. Just as the parallel nature of the actions cannot be destroyed by simply *687tacking on a few more defendants, neither can it be dispelled by repackaging the same issue under different causes of action.

The same is true for Clark’s prayer for equitable relief. Even though an additional remedy is sought in the federal action, the liability issues (which are the central legal issues) remain the same in both cases. Moreover, the relief requested in this case is substantially similar to that requested in the Brewster action. Although Clark states in her complaint that “[pjlaintiff on behalf of Sears has no adequate remedy at law,” both complaints request jury trials and seek to recover damages from the individual defendants. While we are mindful that remedies need not be plead with specificity, Clark’s vague request for equitable relief does not convince us that both lawsuits do not in the end seek substantially the same relief, i.e., damages.

Accordingly, the district court did not abuse its discretion in finding the Breivster and Clark actions parallel. We agree with the district court that the thrust of these lawsuits is the same — they rely on the same factual predicate to raise substantially similar legal issues against substantially similar parties. If we were to reach the opposite conclusion, future federal plaintiffs would have an incentive to tag on redundant and non-essential claims, parties, and remedies to create straw distinctions with an otherwise parallel state proceeding.

B. Exceptional Circumstances

Of course, a conclusion that federal and state proceedings are parallel only begins the inquiry into whether a stay is appropriate under Colorado River. We must now review the district court’s determination that abstention was warranted in this case under the 10-factor “exceptional circumstances” test. As we examine the district court’s analysis, we are guided by the Supreme Court’s instruction that “[n]o one factor is necessarily determinative; a carefully considered judgment taking into account both the obligation to exercise jurisdiction and the combination of factors counselling against that exercise is required.” Colorado River, 424 U.S. at 818-19, 96 S.Ct. 1236. “The weight to be given any one factor is determined solely by the circumstances of the particular case— there is no mechanical formula by which to determine when a stay is appropriate.” Schneider Nat’l Carriers, 903 F.2d at 1157 (citing Moses H. Cone, 460 U.S. at 16, 103 S.Ct. 927).

The district court found that a stay would eliminate piecemeal and duplicative litigation. We agree that this factor weighs in favor of a stay. As explained above, the claims in Clark and Brewster are all predicated on the same showing of a breach of fiduciary duty. Without staying the federal proceeding, the two actions would proceed simultaneously — duplicating the amount of judicial resources required to reach a resolution. If Brewster is reinstated, the two courts would oversee similar pre-trial motions and discovery matters and two different triers of fact would be asked to consider the same issues, evidence and witnesses. Our Court has held that this sort of redundancy counsels in favor of a stay. See Caminiti, 962 F.2d at 701 (concluding that where the same issues must be resolved in two cases, a stay would prevent duplicative and wasteful litigation). Not only would a stay save judicial resources, but it would also protect against the danger of the two proceedings reaching inconsistent results, especially in light of the recent dismissal of Brewster by the New York Supreme Court.

Next, we agree with the district court’s determination that because both cases are *688governed by New York law, it is better to defer to the New York courts to consider the issues presented. “[A] state court’s expertise in applying its own law favors a Colorado River stay.” Day v. Union Mines, Inc., 862 F.2d 652, 660 (7th Cir. 1988). In this case, it makes more sense to allow a New York state court to resolve whether under New York law pre-suit demand was excused and whether a claim for breach of fiduciary duty has been stated against the defendants.

As the district court also noted, the Brewster action was filed first, albeit by only a few weeks.' At best, this factor is neutral, but it does not push us towards allowing the federal case to proceed. The district court also found that a stay was warranted because the “claims here can be adjudicated in New York, and the New York claims cannot be removed here.” Clark does not dispute that the claims in this proceeding may be brought in New York state court. Not only does the availability of concurrent jurisdiction weigh in favor of a stay, so does the inability to remove the New York action to federal court. See Day, 862 F.2d at 659-60 (there is a “policy against hearing a federal claim which is related to ongoing non-removable state proceedings”).

The district court found the remaining factors to be neutral. Of these factors, Clark most vigorously contests the district court’s determination with respect to the relative convenience of the federal forum. To support her argument that the federal forum is more convenient, Clark points out that ten of the fifteen defendants live in this district and that many of the relevant documents and witnesses are located at Sears’ Illinois headquarters. While this may be true, the district court’s finding was not improper. The Brewster action will continue in New York regardless of whether the Clark action is stayed in Illinois. Moreover, the thrust of Clark’s argument regarding convenience of the Illinois forum (as well as her arguments relating to other factors) is that the district court assigned this factor insufficient weight in the its analysis. .However, a disagreement over weight assigned to a factor by the district court does not necessarily amount to an abuse of discretion. Given the flexible nature of the ten-factor balancing test, we are reluctant to tinker with the district court’s assignment of weight to any particular factor.

The remaining factors can be disposed of summarily. No persuasive arguments have been presented as to why any of them would counsel against a stay in this case. Clark does not dispute that two of them — jurisdiction over property and vexatious litigation — are indeed neutral. Moreover, there is no fear that Sears’ rights will not be adequately protected in the state proceeding as the same questions of law and fact are presented as in the federal case and the state court can resolve these questions just as effectively. Lastly, as the motion to dismiss has been fully briefed, argued, and decided in Brewster, the progress of the state court proceeding is currently more advanced than that of the federal action.

Accordingly, since the state and federal proceedings at issue are parallel and a stay would promote wise judicial administration, we decline to hold that the district court abused its discretion in finding that the exceptional nature of this case justified a stay. The district court appropriately addressed the Colorado River factors, applying more significant analysis to those factors most relevant in this ease. Moreover, a stay is a measured approach that protects the substantial rights of the parties and allows Clark the possibility of continuing this litigation once the Brewster action reaches a conclusion in New York.

*689III. Conclusion

We AffiRM the district court’s stay order.