Who was the youngest delegate to sign the United States Constitution?

Jonathan Dayton was the youngest delegate to sign the United States Constitution.

Dayton was 26 years old when he signed the Constitution on September 17, 1787. He represented New Jersey at the Constitutional Convention and was one of four New Jersey delegates whose names appear on the final document.

Dayton later entered national politics. He served in the United States House of Representatives and became Speaker of the House from 1799 to 1805. His name is also attached to Dayton, Ohio, which was named in his honor.

Benjamin Franklin was the oldest signer, aged 81. This creates an unusually wide age range among the signers, from Dayton in his twenties to Franklin in his eighties. Jonathan Dayton should not be confused with James Madison, who was younger than many convention leaders but was not the youngest signer.