Thirty-nine delegates signed the final United States Constitution on September 17, 1787. They signed at Independence Hall in Philadelphia during the final session of the Constitutional Convention.
Seventy-four delegates were selected to attend the convention, but 55 actually participated at some point. Thirteen participants left before the conclusion, and three delegates who remained—Edmund Randolph, George Mason, and Elbridge Gerry—refused to sign.
The 39 signers represented 12 states because Rhode Island declined to send delegates. George Washington, who presided over the convention, signed first. Benjamin Franklin, aged 81, was the oldest signer, while Jonathan Dayton, aged 26, was the youngest. The signing did not immediately make the Constitution law; Article Seven required ratification by nine states.