The United States Post Office and Courthouse was built in 1896 and designed by local architect John Henry Deveraux. An Irish immigrant, Deveraux became a noted architect in Charleston by the late 1860s. His Renaissance Revival style building with lavish interior is indicative of elaborate public buildings of the late 19th century. Deveraux used grey granite from Winnsboro, South Carolina, a square corner tower, rusticated quoins, and balustraded balconies to create a palatial and imposing exterior. The Post Office occupies the first floor, decorated with carved mahogany woodwork, a marble staircase, brass and ironwork, and stone columns. The second floor contains a paneled Victorian courtroom.
The Post Office and Courthouse is the most modern building at the intersection of Meeting and Broad Streets, land that was set aside as a Civic Square in the Grand Modell, the 17th-century plan of the city. The intersection is now called "Four Corners of the Law" as the buildings that surround it reflect ecclesiastical, municipal, state, and federal law, with the Post Office representing the latter.
Prior to this building's construction, the site contained a mid-18th-century guardhouse (police station), treasury building, and the Charleston Club. The guardhouse standing at the time of the 1886 earthquake was damaged so severely it was demolished. In 1983, a large annex was constructed south of the building; another to the west was begun in 1997, after years of planning and debate. The building still functions as it did originally, used as the downtown branch of the post office and federal district court.