The Federal Building and U.S. Courthouse is a historic building in Gainesville, Georgia. It was added to the National Register of Historic Places on January 24, 1974. It is located at 126 Washington Street. Part of the building was constructed in 1910 and used as a Post Office. It was designed by James Knox Taylor. The courthouse was constructed behind this building in 1936. The post office building is marble and both buildings are Neoclassical architecture.