McCreery v. Haskell 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 a prisoner, William McCreery, was held in a federal prison in the state of Missouri. McCreery sought a writ of habeas corpus from the state court, claiming that he was being held in violation of his constitutional rights. The state court granted the writ, and the federal government appealed the decision to the Supreme Court. 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 writ of habeas corpus was a federal remedy, and that the state court did not have the power to interfere with the federal government's authority to imprison individuals. The Court also noted that the writ of habeas corpus was a remedy that could only be used to challenge the legality of a person's detention, and not to challenge the conditions of the detention. The Court's decision in McCreery v. Haskell established that state courts do not have the authority to issue writs of habeas corpus to prisoners held in federal prisons. The decision also clarified the scope of the writ of habeas corpus, and established that it could only be used to challenge the legality of a person's detention, and not to challenge the conditions of the detention.

In McCreery v. Haskell, the United States Supreme Court was asked to decide whether a state court had jurisdiction over an action brought by a non-resident against another non-resident in which the cause of action arose out of events that occurred within the state's borders. The majority opinion held that such jurisdiction did exist and affirmed the decision of the lower court. However, Justice Field dissented from this opinion and argued that it would be unconstitutional for states to exercise extraterritorial power over persons who were not citizens or residents of their respective states. He further argued that if such power existed then it should only be exercised when necessary for public safety or welfare, as opposed to private interests like those at issue in this case. Ultimately, he concluded that since there was no evidence presented showing any need for exercising such authority in this particular instance then it should have been denied by both courts below.