Thirty-nine delegates signed the United States Constitution at the 1787 Philadelphia convention remembered in the history surrounding America250.
The convention included 55 delegates over its course, but not all were present at the final signing and not all approved the completed document. Thirty-nine delegates placed their names on the Constitution on September 17, 1787.
George Washington, who presided over the convention, was among the signers. Benjamin Franklin also signed, becoming the oldest signer at age 81. Several important delegates, including Thomas Jefferson and John Adams, were abroad as diplomats and did not attend.
The Constitution then required ratification by the states. It took effect after New Hampshire became the ninth state to ratify it in June 1788, while Rhode Island ratified later, in 1790. Signing and ratification were separate stages in creating the new government.