Delaware was the first state to ratify the United States Constitution, doing so on December 7, 1787.
Article Seven required approval from conventions in nine states before the Constitution could take effect. Delaware’s convention approved it unanimously, with a vote of 30–0. The state’s early ratification earned it the nickname “The First State.”
Pennsylvania followed five days later, on December 12, 1787. New Jersey, Georgia, and Connecticut were next, and New Hampshire became the ninth state on June 21, 1788, bringing the Constitution into effect.
Delaware is sometimes confused with Pennsylvania because both were among the earliest states to ratify and both hosted important Revolutionary-era events. However, Delaware clearly holds the first-place position in the constitutional ratification sequence.