On what date was the United States Constitution signed, an event remembered by America250?

The United States Constitution was signed on September 17, 1787, an event remembered by America250.

The signing took place at Independence Hall in Philadelphia at the close of the Constitutional Convention. Thirty-nine delegates endorsed the document, representing twelve states. Rhode Island had declined to send delegates, and not every delegate who attended the convention agreed to sign.

The Constitution did not take effect simply because delegates signed it. Article VII required ratification by conventions in nine states. Delaware became the first state to ratify, on December 7, 1787, and New Hampshire became the ninth, on June 21, 1788. The new federal government began operating in 1789.

September 17 is now observed in the United States as Constitution Day and Citizenship Day. The date is sometimes confused with May 25, when the convention reached a quorum, or with June 21, 1788, when the ninth state ratified the document. Those dates mark different stages in the Constitution's creation.