This list of tallest buildings in Washington, D.C. ranks high-rises in the U.S. capital of Washington, D.C. The tallest structure in the city, excluding radio towers, is the Washington Monument, which rises 555 feet (169 m) and was completed in 1884. The structure, however, is not generally considered a high-rise building as it does not have successive floors that can be occupied. The tallest habitable building in the city is the Basilica of the National Shrine of the Immaculate Conception, which rises 329 feet (100 m). The second-tallest building in Washington is the Old Post Office Building, which is 315 feet (96 m) high. The third-tallest building in the city is the Washington National Cathedral, which rises 301 feet (92 m) above grade. The cathedral is built on high ground known as Mou