Delegates signed the United States Constitution on September 17, 1787, a founding event remembered by America250.
The signing occurred at the final session of the Constitutional Convention in Philadelphia’s Pennsylvania State House, now called Independence Hall. George Washington, the convention’s president, signed first, followed by 38 other delegates.
The Constitution created a framework for a federal government with separate legislative, executive, and judicial branches. It did not take effect immediately: the document required ratification by the states, and the new government began operating in 1789.
September 17 is now observed as Constitution Day in the United States. A common mix-up is confusing the signing date with the date of ratification by the required ninth state, New Hampshire, which occurred on June 21, 1788.