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

Jonathan Dayton was the youngest person to sign the United States Constitution, doing so at age 26.

Dayton represented New Jersey at the Constitutional Convention in Philadelphia. Born in 1760, he was much younger than many of the delegates, who were experienced lawyers, statesmen, military officers, and administrators of the Revolutionary era.

After the Constitution was signed, Dayton continued in national politics. He served in the U.S. House of Representatives, became the chamber’s third Speaker, and later represented New Jersey in the Senate.

Dayton is sometimes confused with younger participants in the broader founding era, but the relevant distinction here is among the Constitution’s signers. The convention included many delegates who attended but did not sign, so the youngest signer is not necessarily the youngest person connected with the convention.