Delegates signed the United States Constitution on September 17, 1787, at Independence Hall in Philadelphia.
The signing concluded the Constitutional Convention, which had met in Philadelphia from May 25 through September 17, 1787. The convention had originally been called to improve the Articles of Confederation, but the delegates ultimately drafted an entirely new framework for the federal government.
Thirty-nine delegates signed the final document. They represented twelve states; Rhode Island did not send delegates to the convention. George Washington, who presided over the meeting, signed along with figures including Benjamin Franklin, James Madison, and Alexander Hamilton.
Signing the Constitution did not immediately put it into operation. The document required ratification by conventions in the states, and the new federal government began operating in 1789. September 17 is now observed in the United States as Constitution Day and Citizenship Day, although the Constitution’s ratification process continued for months after the Philadelphia signing.