Which state became the ninth to ratify the United States Constitution?

New Hampshire became the ninth state to ratify the United States Constitution on June 21, 1788.

Article Seven specified that the Constitution would take effect after nine states ratified it. New Hampshire’s approval therefore supplied the required majority and formally placed the new framework of government into operation. The state’s convention voted 57 to 47 in favor after earlier postponing a decision.

The first eight ratifying states were Delaware, Pennsylvania, New Jersey, Georgia, Connecticut, Massachusetts, Maryland, and South Carolina. Virginia and New York ratified soon afterward, but their approval was no longer necessary for the Constitution to become effective once New Hampshire reached number nine.

New Hampshire’s role is sometimes confused with Delaware’s. Delaware was first to ratify, while New Hampshire was ninth and thereby decisive under Article Seven. Rhode Island was the last of the original thirteen states to ratify, waiting until May 29, 1790, after the new federal government had already begun operating.