Thirty-nine delegates signed the United States Constitution at Independence Hall on September 17, 1787.
Seventy-four delegates had been chosen for the Constitutional Convention, but only 55 attended at some point. Thirteen of those participants left before the final ceremony, and three delegates who remained—George Mason, Edmund Randolph, and Elbridge Gerry—refused to sign.
The 39 signers represented twelve states. Rhode Island declined to send delegates to the convention. George Washington signed as convention president, while Benjamin Franklin was the oldest signer at age 81 and Jonathan Dayton was the youngest at age 26.
The number 39 is therefore different from both the 55 delegates who attended and the 74 who were selected. This distinction matters when comparing the Constitution with the Declaration of Independence, which has 56 signatures.