September 17 in American History

September 17, 1787 — the Constitution is signed

After a summer of closed-door debate in Philadelphia, 39 delegates signed the U.S. Constitution — the framework that's governed the country ever since. It still needed ratification by nine states to take effect, but the document itself, argued line by line, was finished this day. Now celebrated as Constitution Day.

★ Founding DaySeptember 17 marks U.S. Constitution — since 1787
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Common Questions About September 17

What happened on September 17 in American history?

In 1787: the Constitution is signed. After a summer of closed-door debate in Philadelphia, 39 delegates signed the U.S.

Why is September 17 significant?

After a summer of closed-door debate in Philadelphia, 39 delegates signed the U.S. Constitution — the framework that's governed the country ever since. It still needed ratification by nine states to take effect, but the document itself, argued line by line, was finished this day. Now celebrated as Constitution Day.

Is September 17 an American holiday or anniversary?

Yes — September 17 marks the anniversary of U.S. Constitution, dating to 1787. Signed in Philadelphia — celebrated as Constitution Day.

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