The Washington Monument is 555 feet tall according to the National Park Service.
The obelisk on the National Mall in Washington, D.C., commemorates George Washington, the first president of the United States. Construction began on July 4, 1848, but work stopped in 1854 because of political and financial difficulties. Building resumed in 1877, and the monument was completed in 1888.
Its height is visually emphasized by a small aluminum apex at the top. The structure uses bluestone gneiss for its foundation, granite inside portions of the monument, and three varieties of white marble in its exterior facing. The change in marble is visible as a color variation partway up the obelisk.
Some references give the height as 554 feet because modern surveying and changes around the entrance produce a slightly different measurement. The National Park Service’s historic measurement is 555 feet, the figure commonly used in visitor information. The monument was the world’s tallest structure from 1884 until the Eiffel Tower surpassed it in 1889.