How tall is the Washington Monument, measured from the ground to its aluminum cap?

The Washington Monument is 555 feet 5⅛ inches tall from the ground to its aluminum cap.

The obelisk in Washington, D.C., honors George Washington, the first president of the United States and commander of the Continental Army. Robert Mills designed the monument, whose construction began in 1848. Work stopped for years because of political conflict, funding problems, and the Civil War.

The monument was completed in 1884 and dedicated in 1885. Its two visibly different stone sections reflect the long construction interruption: the lower portion uses stone from the original building period, while the upper section uses a somewhat different quarry source.

For decades, the Washington Monument was the world’s tallest building and remains one of the most recognizable structures in the United States capital. The aluminum cap at its peak was an unusual nineteenth-century engineering detail and helps define the monument’s precise official height.