United States v. Gilmore et al. was a United States Supreme Court case that dealt with the issue of whether a state court had the authority to issue a writ of habeas corpus to a prisoner held in federal custody. The case arose when the state of California issued a writ of habeas corpus to a prisoner held in federal custody in San Francisco. The United States argued that the state court did not have the authority to issue the writ, as the federal government had exclusive jurisdiction over the prisoner. The Supreme Court agreed with the United States, ruling that the state court did not have the authority to issue the writ. The Court held that the federal government had exclusive jurisdiction over the prisoner, and that the state court could not interfere with the federal government's authority. The Court also held that the writ of habeas corpus was a federal prerogative, and that the state court could not interfere with the federal government's authority in this regard. The Court's decision established the principle that the federal government has exclusive jurisdiction over prisoners held in federal custody, and that state courts cannot interfere with the federal government's authority in this regard.

In United States v. Gilmore et al., the Supreme Court was asked to decide whether a federal court had jurisdiction over an action brought by the United States against two individuals for violating a contract with the government. The majority opinion held that such actions were within federal jurisdiction, but Justice Field dissented on this point. He argued that since contracts are traditionally matters of state law, it would be inappropriate for Congress to grant exclusive authority in these cases to federal courts without clear language indicating its intent. Furthermore, he noted that there is no indication in either the Constitution or any statute passed by Congress granting such power and thus concluded that only state courts have jurisdiction over contract disputes between citizens and their government.