Montana v. Wyoming
138 S. Ct. 758 · Decided February 20, 2018 · 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
Montana v. Wyoming was decided on February 20, 2018 unanimously (8–0). SCDB codes the disposition as “no disposition.” SCDB classifies its main issue as “Miscellaneous interstate conflict” in the Interstate Relations area.
Read the opinion
- CourtListener (Free Law Project) — opinion text
- Supreme Court of the United States — slip opinions, October Term 2017
Case details
- Citations
- 138 S. Ct. 758 · 200 L. Ed. 2d 10 · 2018 U.S. LEXIS 895
- Docket number
- 137, Orig.
- Decided
- February 20, 2018
- Court era
- Roberts Court
- Decision type
- Decree
- Disposition
- No disposition
- Outcome for petitioner
- The petitioning party received a favorable disposition
- Vote
- 8–0 (unanimous)
- Opinion assigned by
- John G. Roberts Jr.
- How the case arrived
- Original jurisdiction
- Issue (SCDB)
- Miscellaneous interstate conflict
- Issue area
- Interstate Relations
- Legal provision
- Interstate compact
- Type of law
- Other
- Decision direction (SCDB)
- Unspecifiable what this means
How the Justices voted
| Justice | Vote | Separate writing |
|---|---|---|
| Justice Anthony M. Kennedy | Majority | |
| Justice Clarence Thomas | Majority | |
| Justice Ruth Bader Ginsburg | Majority | |
| Justice Stephen G. Breyer | Majority | |
| Chief Justice John G. Roberts Jr. | Majority | |
| Justice Samuel A. Alito Jr. | Majority | |
| Justice Sonia Sotomayor | Majority | |
| Justice Neil M. Gorsuch | Majority |
Did not participate: Elena Kagan.
Full case caption
Montana v. Wyoming
SCDB identifiers: case 2017-055, docket 2017-055-01.
Related decisions
Other cases on “Miscellaneous interstate conflict”
- Texas v. New Mexico and Colorado
- Kansas v. Nebraska and Colorado
- Mississippi v. Tennessee
- New York v. New Jersey
- Texas v. New Mexico and Colorado
- Franchise Tax Board of California v. Gilbert P. Hyatt
Cases on the same legal provision: Interstate compact
- Texas v. New Mexico
- Tarrant Regional Water District v. Rudolf John Herrmann
- State of Alabama v. State of North Carolina.
- State of New Jersey v. State of Delaware
- State of Kansas v. State of Colorado
- State of New Jersey v. State of New York
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