Delaware was the first state to ratify the United States Constitution, approving it on December 7, 1787. Its ratifying convention voted unanimously, giving Delaware the nickname “The First State.”
Article VII established the Constitution’s ratification rule: the document would take effect among the states that approved it once nine states had ratified it. Delaware acted first, followed by Pennsylvania on December 12 and New Jersey on December 18. New Hampshire became the crucial ninth state on June 21, 1788.
Delaware’s early approval reflected its small size and close commercial ties with neighboring states. The unanimous vote also contrasted with the more heated debates in larger states, where supporters and opponents argued over federal power, individual liberties, and the absence of a bill of rights.
Rhode Island was the last of the original thirteen states to ratify, doing so on May 29, 1790. The first state to ratify is therefore Delaware, not Pennsylvania, even though Pennsylvania hosted the Constitutional Convention in Philadelphia.