The post office was constructed in 1909, not long after the Warren and Wetmore courthouse was completed. James Knox Taylor, who from 1897 to 1912 was Supervising Architect of the United States Department of the Treasury, is credited ex officio as the architect.
The brick building has a marble Doric portico on the south facade, a marble balustrade, and marble trim. The addition on the east side of the building was added in 1938, probably very soon after this picture, which is dated 1938, was taken.
Another addition was made to the building in 1938: the sculptural relief on the north wall of the lobby, surrounding to the entrance to the post master's office. The relief is the work of Vincent Glinsky and features the explorer Henry Hudson.
Since 1988, the post office building has been individually listed in the National Register of Historic Places.