Thirty-nine delegates signed the United States Constitution on September 17, 1787, a document central to the America250 story.
The signing took place at the Pennsylvania State House, now known as Independence Hall, in Philadelphia. The delegates were concluding the Constitutional Convention, which had met from May 25 through September 17 to replace the Articles of Confederation with a stronger federal framework.
Twelve states sent delegates to the convention; Rhode Island declined to participate. Forty-two delegates were present at the final session, but three—George Mason, Edmund Randolph, and Elbridge Gerry—refused to sign. The remaining 39 endorsed the finished document.
George Washington, who presided over the convention, signed first. Benjamin Franklin was the oldest signer at 81, while Jonathan Dayton was the youngest at 26. Signing did not immediately make the Constitution law: Article Seven required ratification by nine states, and the Constitution took effect after New Hampshire supplied the ninth approval in 1788.