This is a list of former United States counties, a list of United States counties (administrative subunits of a U.S. state) that no longer exist.
They were established by a state, provincial, colonial, or territorial government. Most of these counties were created and disbanded in the 19th century; county boundaries have changed little since 1900 in the vast majority of states. A county is repeated on the list if its jurisdiction changed from one state, colony, or territory to another.
This list includes (but is not limited to) counties that were renamed but retained their territorial integrity, or counties that were transferred wholesale to another state when it was separated from another state (Massachusetts counties transferred to Maine; Virginia counties transferred to Kentucky and West Virginia; and North Carolina counties transferred to Tennessee).