The United States Constitution was signed on September 17, 1787, a later milestone in the history behind America250.
Delegates to the Constitutional Convention signed the Constitution at the Pennsylvania State House in Philadelphia, the same building now known as Independence Hall. The convention had met from May through September 1787 to revise the Articles of Confederation, but it ultimately produced an entirely new framework for the federal government.
Thirty-nine delegates signed the document on September 17. It then required ratification by the states before taking effect. The Constitution became operative in 1789, and the first Congress met that year. The Bill of Rights was ratified in 1791 as the first ten amendments.
September 17 is observed in the United States as Constitution Day and Citizenship Day. It is distinct from July 4, 1776, the date associated with the Declaration of Independence. The two documents are linked historically but mark different stages in the creation of the United States.