Thirty-nine delegates signed the United States Constitution at its 1787 convention, a founding milestone highlighted by America250.
The signing took place on September 17, 1787, at the Pennsylvania State House in Philadelphia, now known as Independence Hall. The Constitutional Convention had begun in May with a larger group of appointed delegates, but not everyone attended every session or remained until the final day.
In total, 55 delegates attended at least part of the convention, and 42 remained when the final document was presented. Three of those remaining delegates declined to sign, leaving 39 signatures. Rhode Island sent no delegates to the convention, while the other twelve states were represented.
The signatures did not themselves put the Constitution into operation. Article VII required ratification by conventions in nine states. New Hampshire became the ninth state to ratify on June 21, 1788, allowing the Constitution to take effect. Rhode Island, the last of the original states to ratify, did so in 1790.