What Is Diversity Jurisdiction?

Diversity jurisdiction is a federal court’s authority to hear a civil case between citizens of different states when the amount in controversy exceeds $75,000. Codified at 28 U.S.C. § 1332, it requires complete diversity — no plaintiff may share a home state with any defendant — a rule traced to Strawbridge v. Curtiss.

This article explains what diversity jurisdiction is, how complete diversity and the amount-in-controversy requirement work, how citizenship is determined for individuals and entities, and why the doctrine drives so much removal and remand litigation. For personal injury practitioners, the choice of forum often turns on these rules, so a precise command of them is essential.

What Is Diversity Jurisdiction and How Does It Work?

Diversity jurisdiction gives federal district courts subject-matter jurisdiction over state-law claims when the parties are citizens of different states and enough money is at stake. It exists alongside federal-question jurisdiction and rests on the constitutional grant in Article III, implemented by Congress through 28 U.S.C. § 1332. The historical rationale is the fear that an out-of-state litigant might face bias in a local court, so the federal forum offers a neutral alternative. Because a diversity case applies state substantive law under the Erie doctrine, the federal court decides a state-law claim using state rules of decision while following federal procedure.

Two independent requirements must both be satisfied:

• The parties must be diverse in citizenship, meaning no plaintiff shares a state of citizenship with any defendant.
• The amount in controversy must exceed $75,000, exclusive of interest and costs.
• The claim itself is typically one of state law, such as negligence, since a federal-question claim would supply its own basis for jurisdiction.
• Diversity is measured at the time the complaint is filed, and later changes in a party’s citizenship generally do not defeat it.

What Does “Complete Diversity” Require?

Complete diversity requires that every plaintiff be a citizen of a different state from every defendant, without exception. The rule comes from Chief Justice Marshall’s decision in Strawbridge v. Curtiss, 7 U.S. 267 (1806), which read the diversity statute to demand total diversity of citizenship among opposing parties. A single non-diverse defendant destroys jurisdiction for the entire case, which is why the citizenship of every named party matters. This is distinct from the constitutional minimum, under which the Supreme Court has said only minimal diversity is required — Congress has simply chosen to demand more in the general diversity statute.

Citizenship is determined differently depending on the type of party:

• An individual is a citizen of the state of their domicile — their true, fixed home and the place they intend to remain — not merely where they reside.
• A corporation is a citizen of both its state of incorporation and the state of its principal place of business, the “nerve center” under Hertz Corp. v. Friend.
• An unincorporated entity, such as an LLC or partnership, takes the citizenship of each of its members or partners.
• The presence of even one non-diverse party on the wrong side of the caption defeats complete diversity.

How Is the Amount-in-Controversy Requirement Met?

The amount in controversy must exceed $75,000, and courts generally accept the plaintiff’s good-faith allegation of that amount unless it appears to a legal certainty that the claim is worth less. This standard comes from St. Paul Mercury Indemnity Co. v. Red Cab Co. and gives the pleader considerable latitude at the outset. A single plaintiff may aggregate all claims against a single defendant to reach the threshold, but multiple plaintiffs generally cannot combine separate and distinct claims. Where a defendant removes and disputes the figure, the removing party must show by a preponderance of the evidence that the stakes more likely than not exceed $75,000.

The mechanics of the requirement follow a familiar sequence:

1. The plaintiff pleads damages in good faith, and that allegation controls unless legally impossible to satisfy.
2. A single plaintiff may aggregate multiple claims against one defendant to clear the threshold.
3. Separate claims of different plaintiffs usually cannot be combined, though supplemental jurisdiction may sweep in a co-plaintiff who falls just short.
4. On a contested removal, the defendant must prove the jurisdictional amount by a preponderance of the evidence.

How Does Diversity Jurisdiction Affect Personal Injury Litigation?

Diversity jurisdiction routinely determines whether an injury case stays in state court or moves to federal court, shaping strategy from the first pleading. Plaintiffs who prefer a state forum may name a non-diverse defendant, plead damages below the threshold where honest or structure the case to avoid the federal courthouse, while defendants who prefer federal court watch for a basis to remove. The doctrine therefore sits at the center of the removal to federal court and motion to remand cluster that defines early procedural skirmishing in many cases.

The practical consequences for litigants include:

• A defendant sued in state court may remove to federal court if complete diversity and the amount in controversy exist and no defendant is a citizen of the forum state.
• A plaintiff can defeat removal by keeping a properly joined, non-diverse defendant in the case, though fraudulent joinder will not work.
• The distinction between diversity and personal jurisdiction versus subject-matter jurisdiction matters, because diversity is a species of subject-matter jurisdiction that can be raised at any time.
• Where a more convenient forum exists, forum non conveniens may still send a properly filed diversity case elsewhere.

Because subject-matter jurisdiction cannot be waived or created by consent, a defect in diversity can unravel a case even after judgment, when a court discovers that a non-diverse party was present all along. That fragility is why careful counsel confirm the citizenship of every party — including the members of every LLC — before relying on the federal forum.

Conclusion

Diversity jurisdiction is the federal courts’ authority under 28 U.S.C. § 1332 to hear disputes between citizens of different states when more than $75,000 is at stake, and it rests on the complete-diversity rule of Strawbridge v. Curtiss. Determining citizenship for corporations and unincorporated entities, and pinning down the amount in controversy, are the recurring battlegrounds. Because a diversity defect can be raised at any time and defeats jurisdiction outright, practitioners should verify every party’s citizenship early and confirm the amount in controversy before choosing or contesting the federal forum.

Frequently Asked Questions