Thirty-nine delegates endorsed the United States Constitution at Independence Hall on September 17, 1787.
The signing occurred at the Pennsylvania State House in Philadelphia, the same building where the Declaration of Independence had been adopted. The delegates had met for a four-month Constitutional Convention to revise the national system created under the Articles of Confederation.
The 39 signers represented twelve states. Rhode Island did not send delegates to the convention. George Washington presided over the proceedings, while the convention’s secretary, William Jackson, added a note authenticating several handwritten corrections in the final document.
Endorsement by convention delegates did not itself complete ratification. The Constitution required approval by state conventions, and it took effect after the ninth state ratified it in 1788. The new government began operating in 1789, making the Constitution a later milestone connected to, but separate from, the 1776 independence anniversary.