Delaware was the first U.S. state to ratify the Constitution, on December 7, 1787.
Delaware’s ratifying convention met in Dover, where all 30 delegates voted in favor. The unanimous decision earned Delaware its enduring nickname, “The First State.” Its early approval helped begin the sequence by which the 13 states considered the proposed Constitution.
Article Seven required nine states to ratify the document before it could take effect among the ratifying states. New Hampshire became the ninth state on June 21, 1788, but the full process continued until Rhode Island ratified in 1790.
Delaware’s ratification should not be confused with the Constitution’s signing in Philadelphia on September 17, 1787, or its later implementation. Ratification was the state-level approval that made the new federal framework legally operative.