When does a federal court have subject matter jurisdiction?
A federal court has subject matter jurisdiction when Congress has authorized it to hear the case, most commonly through federal question jurisdiction under 28 U.S.C. § 1331 or diversity jurisdiction under 28 U.S.C. § 1332. In broad terms, the case must either arise under federal law or satisfy the statutory requirements for diversity, including the amount in controversy and citizenship requirements.[1][2][4][6]
Core Bases of Subject Matter Jurisdiction
| Basis | Statutory Source | Basic Requirement |
|---|---|---|
| Federal question | 28 U.S.C. § 1331 | Civil action “arising under” the Constitution, laws, or treaties of the United States |
| Diversity | 28 U.S.C. § 1332 | Complete diversity between plaintiffs and defendants, plus amount in controversy exceeding $75,000 |
| CAFA class actions | 28 U.S.C. § 1332(d) | Minimal diversity, aggregate amount in controversy over $5,000,000, and other statutory conditions |
Federal Question Jurisdiction
Under 28 U.S.C. § 1331, the district courts have original jurisdiction over “all civil actions arising under the Constitution, laws, or treaties of the United States.”[3][6]
If the plaintiff’s well-pleaded claim turns on federal law, federal question jurisdiction generally exists. The amount in controversy is not a requirement for jurisdiction under 28 U.S.C. § 1331.[3]
Diversity Jurisdiction
Under 28 U.S.C. § 1332(a), diversity jurisdiction exists when the amount in controversy exceeds $75,000, exclusive of interest and costs, and the case is between citizens of different states, or other statutorily specified parties.[4][5]
Key points:
- Complete diversity is required in ordinary diversity cases: no plaintiff may share state citizenship with any defendant.[1][2][4]
- A corporation is a citizen of both its state of incorporation and its principal place of business.[1][4]
- Diversity jurisdiction is subject to the amount-in-controversy requirement of more than $75,000.[1][4][5]
CAFA Class Actions
For certain class actions, Congress relaxed the citizenship requirement through the Class Action Fairness Act.[2][4][5]
Under 28 U.S.C. § 1332(d), federal jurisdiction may exist if:
- the aggregated amount in controversy exceeds $5,000,000,
- there is minimal diversity (at least one plaintiff is diverse from at least one defendant),
- and the other CAFA requirements are met.[2][4][5]
Bottom Line
A federal court has subject matter jurisdiction only if a statute or constitutional grant authorizes it. The two most common pathways are:
- the case arises under federal law under 28 U.S.C. § 1331, or
- the case satisfies diversity jurisdiction under 28 U.S.C. § 1332.