Delaware was the first state to ratify the U.S. Constitution, approving it on December 7, 1787.
Article Seven required approval from nine of the thirteen states for the Constitution to take effect. State conventions, rather than ordinary legislative votes, considered the document. Delaware's convention accepted it unanimously, with 30 delegates voting in favor and none against.
Pennsylvania followed five days later, while New Jersey, Georgia, and Connecticut ratified before the required ninth state, New Hampshire, approved the Constitution on June 21, 1788. That ninth ratification placed the new constitutional framework into effect, although the remaining states had not yet agreed.
Delaware's early approval helped earn it the nickname “The First State.” It is sometimes confused with Pennsylvania because Philadelphia hosted the Constitutional Convention and became the seat of the new federal government. Delaware was first to ratify, while Rhode Island was the last of the original thirteen states, joining on May 29, 1790.