The United States Post Office, Custom House, and Courthouse is an historic building of the United States government in Fernandina Beach, Florida. It was constructed in the locally popular Renaissance Revival architecture style, and was completed in 1912 under the supervision of James Knox Taylor, Supervising Architect of the United States Treasury Department. The building sits at the intersection of 4th and Centre Streets, across from another historic Court House, and adjacent to the pre-Civil War Victorian Lesesne House. It is three stories, comprising 18,800 square feet (1,750 m2), including a basement and a partial attic.