Delaware became the first state to ratify the U.S. Constitution, doing so on December 7, 1787.
Article Seven required nine state ratifications for the Constitution to take effect. Delaware's convention approved the document unanimously, with a vote of 30–0, making it the first state to accept the proposed federal framework.
The Constitution had been signed in Philadelphia on September 17, 1787, after months of debate at the Constitutional Convention. Ratification then moved through state conventions rather than direct nationwide voting, and each state had to decide whether to join the new system.
Delaware's early approval earned it the nickname “The First State.” New Hampshire became the ninth state to ratify on June 21, 1788, bringing the Constitution into effect. Rhode Island was the last of the original thirteen states to ratify, on May 29, 1790.