Walkley v. City of Muscatine was a case heard by the United States Supreme Court in 1867. The case involved a dispute between the City of Muscatine and a local resident, John Walkley. Walkley had been arrested and fined for operating a ferry without a license. He argued that the city had no authority to require a license, as the ferry was located on the Mississippi River, which was a navigable waterway and thus under the jurisdiction of the federal government. The Supreme Court agreed with Walkley, ruling that the city had no authority to require a license for the ferry. The Court held that the federal government had exclusive jurisdiction over navigable waters, and that the city could not interfere with the operation of a ferry on such waters. The Court also held that the city had no authority to impose a fine on Walkley for operating the ferry without a license. This ruling established the principle that the federal government has exclusive jurisdiction over navigable waters, and that local governments cannot interfere with the operation of ferries on such waters.

In Walkley v. City of Muscatine, the Supreme Court was asked to decide whether a city ordinance that required all persons who kept horses or mules within the limits of the city to pay an annual tax for each animal violated constitutional rights. The majority opinion held that such ordinances were valid and did not violate any constitutional provisions. However, Justice Field dissented from this decision and argued that while cities had broad powers in regulating their affairs, they could not pass laws which infringed upon fundamental rights guaranteed by state constitutions or federal statutes. He further argued that since there was no provision in either document granting cities authority over taxation of animals owned by individuals, it would be unconstitutional for them to do so without express permission from higher authorities.