The Custom House and Old Post Office is a historic site located at 281 Front Street, Key West, Florida, United States.

The Custom House currently serves as the Key West Museum of Art & History, which is one of four museums operated by the Key West Art & Historical Society.

Exhibits include local history, famous personalities including Ernest Hemingway, maritime history, and works by local artists.

The United States District Court for the Southern District of Florida met here from its completion until 1932, when the building was transferred to the United States Navy.

This article about a property in Monroe County, Florida on the National Register of Historic Places is a stub.