Ford v. United States is a United States Supreme Court case that was decided in 1886. The case involved a dispute between the United States and the Ford family over the ownership of a tract of land in the state of Mississippi. The United States had acquired the land in 1841, but the Ford family claimed that they had purchased the land from the Chickasaw Indians in 1836. The Supreme Court held that the United States had acquired the land in 1841 and that the Ford family had no valid claim to the land. The Court also held that the United States had the right to take possession of the land without compensating the Ford family. The decision was significant in that it established the principle that the United States could acquire land from Native American tribes without compensating them. The decision also established the principle that the United States could take possession of land without compensating the original owners.

Justice Field delivered the dissenting opinion in Ford v. United States, arguing that Congress had exceeded its constitutional authority by enacting a law which allowed for the forfeiture of property without due process of law. He argued that this was an unconstitutional deprivation of property and violated the Fifth Amendment's guarantee against taking private property for public use without just compensation. Justice Field further contended that Congress could not pass laws to punish individuals or deprive them of their rights unless it was expressly authorized by the Constitution, and there were no such provisions here. He concluded his dissent with a warning about allowing government power to expand beyond what is constitutionally permissible: "The tendency must be resisted at all hazards if our Government is to remain one founded upon free principles."