when was the us constitution ratified

The U.S. Constitution was ratified on June 21, 1788, when New Hampshire became the ninth state to ratify it, meeting the requirement of nine states needed for the Constitution to become the official framework of the government of the United States. The ratification process started after the Constitution was signed on September 17, 1787, and continued until all 13 states had eventually ratified it, with the final state, Rhode Island, ratifying on May 29, 1790.