The cornerstone of the United States Capitol was laid in 1793.
The ceremony took place on September 18, 1793, in Washington, D.C., while the Capitol’s foundations were being excavated. President George Washington led the formal event, accompanied by Freemasons from Virginia, Maryland, Georgetown, and the federal city. Washington placed a commemorative plate in the foundation trench before the cornerstone was lowered.
The ceremony followed Masonic customs, including striking the stone three times with a gavel and offering corn, wine, and oil. A 15-gun salute represented the 15 states then in the Union. The stone itself was made by Georgetown silversmith Caleb Bentley.
A common mix-up is confusing the Capitol’s cornerstone with the building’s later construction milestones. The cornerstone ceremony occurred in 1793, but the Capitol was built, expanded, and redesigned over many decades. The building’s original design also involved several contributors rather than one architect, including William Thornton, whose winning plan was selected after a design competition.