Clark v. Reyburn 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 a federal prison. The case arose when a prisoner, William Clark, was held in a federal prison in the District of Columbia. Clark sought a writ of habeas corpus from the Supreme Court of the District of Columbia, which was denied. Clark then appealed to the Supreme Court of the United States. The Supreme Court held that the state court did not have the authority to issue a writ of habeas corpus to a prisoner held in a federal prison. The Court reasoned that the power to issue a writ of habeas corpus was a federal power, and that the state court did not have the authority to interfere with the federal government's power to imprison individuals. The Court also noted that the writ of habeas corpus was a fundamental right, and that the federal government had the power to protect that right. The Court's decision in Clark v. Reyburn established that the federal government had the exclusive power to issue writs of habeas corpus to prisoners held in federal prisons. This decision has been cited in numerous subsequent cases, and has been used to support the idea that the federal government has the exclusive power to protect the fundamental rights of individuals.

In Clark v. Reyburn, the Supreme Court was asked to decide whether a state court had jurisdiction over an action brought by a citizen of one state against another in which the cause of action arose from events that occurred outside both states. The majority opinion held that such actions could not be heard in any state court and must instead be brought before federal courts. Justice Field dissented, arguing that Congress did not intend for all cases involving citizens of different states to go exclusively through federal courts; rather, he argued, it was up to each individual state's legislature to determine what types of cases they would hear and how those cases should proceed. He further noted that if Congress wanted exclusive jurisdiction over these matters then it should have explicitly stated so when passing legislation on this issue. As such, he concluded that the lower court's decision should stand as there is no evidence indicating otherwise