Twelve states were represented when delegates signed the United States Constitution in 1787, a milestone remembered during America250.
The signing took place at Independence Hall in Philadelphia on September 17, 1787. Delegates from twelve states endorsed the document; Rhode Island had declined to send delegates to the Constitutional Convention.
Thirty-nine delegates signed the Constitution. The number of signers and the number of represented states are different figures, which creates a common source of confusion. Several delegates who attended the convention also refused to sign, including George Mason, Edmund Randolph, and Elbridge Gerry.
The Constitution still required ratification by state conventions before taking effect. Article VII specified that approval by nine states would be sufficient for establishment among the ratifying states. New Hampshire became the ninth state to ratify in June 1788, while Rhode Island joined the Union under the Constitution in 1790.