The U.S. Constitution was signed at Independence Hall on September 17, 1787, a site central to America250 history.
The signing concluded the Constitutional Convention in Philadelphia. Thirty-nine delegates endorsed the completed document, representing twelve states; Rhode Island had declined to send delegates to the convention.
The date is often confused with July 4, 1776, when the Declaration of Independence was adopted in the same building. The two documents belong to different stages of the nation’s founding: the Declaration announced separation from Great Britain, while the Constitution established a framework for the federal government.
The Constitution did not take effect immediately on the signing date. It required ratification by the states, and the new federal government began operating in 1789. Independence Hall therefore connects two separate milestones that America250 encourages visitors to understand together: the declaration of independence and the later creation of the constitutional system.