Louis v. Brown Township is a United States Supreme Court case that was decided in 1883. The case involved a dispute between the plaintiff, Louis, and the defendant, Brown Township, over the ownership of a piece of land. Louis claimed that he had purchased the land from the township in 1876, but the township argued that the sale was invalid because it had not been approved by the township board. The Supreme Court ruled in favor of Louis, finding that the sale was valid and that Louis was the rightful owner of the land. The Court held that the township had no authority to invalidate the sale, as it had not been approved by the board. The Court also held that the township was liable for damages to Louis for the wrongful refusal to recognize the sale. The decision in Louis v. Brown Township established that a township cannot invalidate a sale of land without the approval of the board, and that the township is liable for damages if it wrongfully refuses to recognize the sale. This decision has been cited in numerous subsequent cases involving disputes over the ownership of land.

In the case of Louis v. Brown Township, Justice Field delivered a dissenting opinion in which he argued that the majority's decision was wrongfully based on an interpretation of state law rather than federal law. He asserted that Congress had exclusive power to regulate commerce between states and territories, and thus any regulation by a state or local government would be invalid if it interfered with this power. Furthermore, he argued that since the plaintiff's property was located within two miles of a navigable river, it should have been considered part of interstate commerce and therefore subject to congressional authority instead of being regulated by local governments. As such, Justice Field concluded that the lower court ruling should have been reversed because it violated Congress' exclusive right to regulate interstate commerce.