The 1787 Constitutional Convention that produced the United States Constitution met in Philadelphia.
Delegates gathered at the Pennsylvania State House, the building now known as Independence Hall. The convention began on May 25, 1787, after travel delays prevented a quorum on its originally planned opening date. George Washington was unanimously chosen to preside.
The meeting was initially called to revise the Articles of Confederation, but delegates soon decided to design an entirely new system of government. The convention lasted until September 17 and produced a framework with legislative, executive, and judicial branches. Philadelphia had already hosted the Continental Congress when it adopted the Declaration of Independence in 1776, making the city central to several key events in the founding era.