United States v. Baltimore is a United States Supreme Court case that was decided in 1878. The case involved a dispute between the United States and the City of Baltimore over the ownership of a parcel of land in Baltimore. The United States claimed that the land was part of a federal reservation and thus belonged to the United States. The City of Baltimore argued that the land was part of the city and thus belonged to the city. The Supreme Court held that the land belonged to the United States. The Court reasoned that the land was part of a federal reservation and thus belonged to the United States. The Court also noted that the City of Baltimore had not taken any steps to assert its ownership of the land. The Court concluded that the United States had a superior right to the land and that the City of Baltimore had no right to the land. In conclusion, the Supreme Court held that the land belonged to the United States and not to the City of Baltimore. The Court reasoned that the land was part of a federal reservation and thus belonged to the United States. The Court also noted that the City of Baltimore had not taken any steps to assert its ownership of the land.

In United States v. Baltimore, the Supreme Court was asked to decide whether a tax imposed by Congress on certain imported goods violated the Constitution. The majority opinion held that it did not violate the Constitution and upheld the tax. However, Justice Field dissented from this decision, arguing that Congress had exceeded its authority in imposing such a tax without first obtaining consent from Maryland or any of its citizens who would be affected by it. He argued that while Congress has broad powers under Article I of the Constitution for taxation purposes, those powers must still be exercised within limits set out in other parts of the document as well as established principles of federalism which require state consent before taxes can be levied upon them or their citizens. As no such consent had been obtained here, he concluded that this particular exercise of congressional power was unconstitutional and should have been struck down by the court