Who was the youngest signer of the United States Constitution?

Jonathan Dayton was the youngest signer of the United States Constitution, signing at age 26.

Dayton was a New Jersey delegate to the Constitutional Convention and had been born on October 16, 1760. He was still in his twenties when the Constitution was signed in Philadelphia on September 17, 1787. His youth contrasted with the long political and military experience of many other delegates.

Benjamin Franklin, aged 81, was the oldest signer. George Washington, who was 55, presided over the convention and signed first. James Madison, Alexander Hamilton, and Gouverneur Morris were among the influential delegates involved in drafting and advocating for the document, but none was the youngest signer.

Dayton later served in the new federal government. He became a member of the United States House of Representatives and eventually served as Speaker of the House. The Constitution bears the signatures of 39 delegates, although 55 delegates participated in the convention and three delegates present at the end refused to sign.