Where did delegates sign the U.S. Constitution in 1787?

Delegates signed the U.S. Constitution in Philadelphia on September 17, 1787.

The Constitutional Convention met at the Pennsylvania State House, the building now known as Independence Hall. Delegates from twelve states attended at different points; Rhode Island did not send delegates. George Washington presided over the convention, while James Madison kept extensive notes and became a major contributor to the plan.

The convention had originally been called to revise the Articles of Confederation. Instead, delegates produced an entirely new framework for a federal government with separate legislative, executive, and judicial branches. The document also included a system of checks and balances.

Thirty-nine delegates signed the Constitution on the final day, though several delegates who attended the convention refused to sign or left before the conclusion. The Constitution then required ratification by the states before taking effect. It became operative in 1789, after the necessary states approved it.