State of Illinois v. Commonwealth of Kentucky
500 U.S. 380 · Decided May 28, 1991 · Supreme Court of the United States
Record summary. This page is generated from the Supreme Court Database’s coded data about the case. It describes who decided what, not the Court’s reasoning. Read the opinion itself before relying on it. Not legal advice.
At a glance
State of Illinois v. Commonwealth of Kentucky was decided on May 28, 1991 unanimously (9–0). Justice David H. Souter wrote the opinion of the Court. SCDB classifies its main issue as “Boundary dispute between states” in the Interstate Relations area.
Read the opinion
Case details
- Citations
- 500 U.S. 380 · 111 S. Ct. 1877 · 114 L. Ed. 2d 420 · 1991 U.S. LEXIS 2914
- Docket number
- 106 ORIG
- Decided
- May 28, 1991
- Argued
- March 18, 1991
- Court era
- Rehnquist Court
- Decision type
- Opinion of the Court (orally argued)
- Outcome for petitioner
- The petitioning party received a favorable disposition
- Vote
- 9–0 (unanimous)
- Majority opinion
- David H. Souter
- Opinion assigned by
- William H. Rehnquist
- How the case arrived
- Original jurisdiction
- Issue (SCDB)
- Boundary dispute between states
- Issue area
- Interstate Relations
- Decision direction (SCDB)
- Unspecifiable what this means
How the Justices voted
| Justice | Vote | Separate writing |
|---|---|---|
| Justice Byron R. White | Majority | |
| Justice Thurgood Marshall | Majority | |
| Justice Harry A. Blackmun | Majority | |
| Chief Justice William H. Rehnquist | Majority | |
| Justice John Paul Stevens | Majority | |
| Justice Sandra Day O'Connor | Majority | |
| Justice Antonin Scalia | Majority | |
| Justice Anthony M. Kennedy | Majority | |
| Justice David H. Souter | Majority | Wrote an opinion |
Full case caption
State of Illinois v. Commonwealth of Kentucky
SCDB identifiers: case 1990-086, docket 1990-086-01.
Related decisions
Other cases on “Boundary dispute between states”
- Georgia v. South Carolina
- United States of America v. State of Louisiana
- Louisiana v. Mississippi
- State of Louisiana v. State of Mississippi
- Kentucky v. Indiana
- Oklahoma v. Arkansas
Same Term, same area (Interstate Relations)
Source: Supreme Court Database, 2026 Release 01 (data file dated September 8, 2026). Imported into CaseTrail November 5, 2026. Coverage: decisions from the 1946 through 2025 Terms. Methodology · Report an error