The United States Constitution was signed in Philadelphia in 1787.
Delegates signed the document on September 17, 1787, at the Pennsylvania State House, now called Independence Hall. The convention had met for months to address weaknesses in the Articles of Confederation and created a stronger federal system instead.
Thirty-nine of the 55 delegates present signed the final document. George Washington, who chaired the convention, signed it along with figures such as Benjamin Franklin, James Madison, and Alexander Hamilton. Several delegates opposed the document or had already left Philadelphia.
The Constitution did not become effective simply because it was signed. It required ratification by nine states, which occurred in 1788. The new federal government began operations in 1789, the year Washington became president. These milestones are distinct from the 1776 declaration commemorated by America250.