Exxon Corp. v. Governor of Maryland, 437 U.S. 117 (1978), was a case in which the Supreme Court of the United States upheld a Maryland law prohibiting oil producers and refiners from operating service stations within its borders. The challengers, including Exxon, claimed that the law violated the Dormant Commerce Clause. Justice Stevens wrote for the majority, which disagreed with Exxon et al.: "Since Maryland's entire gasoline supply flows in interstate commerce and since there are no local producers or refiners, such claims of disparate treatment between interstate and local commerce would be meritless." Exxon challenged the Maryland statute in Circuit Court which ruled the statute invalid. The Maryland Court of Appeals reversed the ruling.