For America250, 39 delegates signed the U.S. Constitution in 1787.
The signing took place on September 17, 1787, at the conclusion of the Constitutional Convention in Philadelphia. The convention had originally involved 55 delegates at different points, but not all remained until the final session, and three delegates present refused to sign.
The 39 signers represented 12 states. Rhode Island did not send delegates to the convention, so it was not represented at the signing. George Washington, who presided over the convention, signed first, followed by the other delegates.
Signing did not immediately make the Constitution the operating law of the country. The document still had to be ratified by state conventions. Article VII required approval from nine states, and the new government began under the Constitution in 1789.