Twelve states were represented at the 1787 United States Constitutional Convention.
Delegates from 12 of the 13 states attended the convention in Philadelphia. Rhode Island was the sole state that refused to send delegates, largely because its leaders opposed strengthening the national government.
The convention was authorized to revise the Articles of Confederation, but the delegates eventually drafted an entirely new Constitution. George Washington presided, while James Madison, Alexander Hamilton, and other delegates played major roles in shaping the document.
The number 12 is sometimes confused with the number of states that ratified the Constitution before it took effect, or with the 13 original states. The convention’s final document was signed by 39 delegates representing the 12 participating states.