The United States Constitution was signed on September 17, 1787. Delegates to the Constitutional Convention in Philadelphia approved the document after months of debate over federal power, representation, taxation, and the presidency.
The signing did not immediately make the Constitution operative. It still required ratification by nine states, the threshold specified in Article VII. New Hampshire became the ninth state to ratify on June 21, 1788, and 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 June 21, the ratification date, or March 4, 1789, when the Constitution's government formally began. America250 provides an opportunity to connect the 1787 framework with the nation's 250-year story.