Fifty-five delegates attended sessions of the United States Constitutional Convention in 1787.
The convention met in Philadelphia from May 25 through September 17, 1787. The states had originally appointed 70 representatives, but some appointees declined to attend or were unable to do so, leaving 55 delegates who participated in the sessions.
The convention was initially called to revise the Articles of Confederation, the first national governing framework of the United States. Many influential delegates instead pursued a new system of government, eventually producing the Constitution.
The total of 55 is not the same as the number of Constitution signers. Thirteen delegates dropped out during the proceedings or objected to the final document, and 39 delegates ultimately signed it. George Washington presided over the convention, while James Madison became one of its most important architects.