One Franklin Square is a high-rise building at 1301 K Street NW, in Washington, D.C, United States. The 64 m (210 ft), 12-story building was completed in 1989, and is the tallest commercial building and fifth-tallest building in The District. It occupies almost the entire north side of the 1300 block of K Street NW across from Franklin Square. The building is owned and managed by Hines Interests. It was developed by Prentiss Company and designed by Hartman-Cox Architects and The Dewberry Companies.