United States v. New Orleans was a United States Supreme Court case that dealt with the issue of whether the United States had the right to take possession of a portion of the city of New Orleans for the purpose of constructing a custom house. The case was brought by the United States against the City of New Orleans, and the Supreme Court ultimately ruled in favor of the United States. The case arose when the United States sought to take possession of a portion of the city of New Orleans for the purpose of constructing a custom house. The City of New Orleans argued that the United States did not have the right to take possession of the land without the consent of the city. The Supreme Court disagreed, ruling that the United States had the right to take possession of the land for the purpose of constructing a custom house. The Court reasoned that the United States had the right to take possession of the land for the purpose of constructing a custom house because it was necessary for the efficient collection of revenue. In its decision, the Supreme Court also held that the United States had the right to take possession of the land without the consent of the city, as long as the United States paid just compensation for the land. The Court reasoned that the United States had the right to take possession of the land for the purpose of constructing a custom house, and that the city was not entitled to compensation for the taking of the land. In conclusion, the Supreme Court ruled in favor of the United States, holding that the United States had the right to take possession of a portion of the city of New Orleans for the purpose of constructing a custom house, without the consent of the city, as long as the United States paid just compensation for the land.

In United States v. New Orleans, the Supreme Court was asked to decide whether a federal statute that authorized the Secretary of War to take possession of certain public lands in Louisiana for military purposes was constitutional. The majority opinion held that Congress had authority under Article I, Section 8 of the Constitution to pass such legislation and thus it did not violate any provision of the Constitution. Justice Field dissented from this decision arguing that while Congress may have been able to pass such legislation under its enumerated powers, it could not do so without violating other provisions within the Constitution which protect states' rights and sovereignty over their own land. He argued further that if Congress were allowed unchecked power in this regard then they would be able to encroach upon state's rights with impunity and ultimately lead towards an erosion of state autonomy as well as individual liberty.