Dayton v. Lash 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 who was being held in a federal prison. The case arose when the state of Ohio attempted to issue a writ of habeas corpus to a prisoner who was being held in a federal prison in the state of Indiana. The prisoner, Dayton, had been convicted of a crime in Indiana and was serving his sentence in a federal prison in that state. The Supreme Court held that the state court did not have the authority to issue a writ of habeas corpus to a prisoner who was being held in a federal prison. The Court reasoned that the writ of habeas corpus was a remedy that was available only to prisoners who were being held in state prisons, and not to those who were being held in federal prisons. The Court also noted that the writ of habeas corpus was a remedy that was available only to prisoners who were being held in the state in which the writ was issued. The Court's decision in Dayton v. Lash established that state courts do not have the authority to issue writs of habeas corpus to prisoners who are being held in federal prisons. This decision has been cited in numerous subsequent cases involving the issue of whether a state court has the authority to issue a writ of habeas corpus to a prisoner who is being held in a federal prison.

In Dayton v. Lash, the Supreme Court was asked to decide whether a state court had jurisdiction over a case involving an alleged breach of contract between two citizens from different states. The majority opinion held that the state court did not have jurisdiction in this matter because it involved interstate commerce and thus fell under federal authority. However, Justice Field dissented from this decision on the grounds that Congress had not yet passed any legislation granting exclusive power to regulate interstate commerce to the federal government; therefore, he argued that such matters should still be left up to individual states until Congress acted otherwise. He further contended that if every dispute between citizens of different states were subject only to federal regulation then there would be no need for separate state courts at all since they could never exercise their own powers in such cases. As such, Justice Field concluded by arguing against allowing one branch of government (the judiciary) preempt another (the legislature) when it came to regulating interstate commerce before Congress had even taken action on the issue itself.