Delegates met in Philadelphia for the Constitutional Convention that produced the U.S. Constitution in 1787.
The convention met from May 25 to September 17, 1787, at the Pennsylvania State House, now known as Independence Hall. Delegates originally gathered to revise the Articles of Confederation, but they soon decided to create an entirely new framework for national government.
George Washington presided over the convention. James Madison arrived with extensive notes and proposals, while delegates debated representation, executive power, taxation, commerce, slavery, and the relationship between state and federal authority. Major compromises helped produce a document that could be submitted to the states for ratification.
The Constitution was signed on September 17, 1787, by 39 of the 42 delegates still present. It did not take effect immediately: nine states had to ratify it under Article Seven, and that threshold was reached in June 1788. The new federal government began operating in 1789.