The United States Constitution, which Congress created and signed in its final draft form on September 17, 1787, obtained the required nine-state approval for ratification 9 months later when New Hampshire became the ninth state to vote to ratify in June 1788. The first state to vote to ratify was Delaware on December 7, 1787. The last of the 13 original states to vote for ratification was Rhode Island in May 1790, 2 years and 8 months after the Constitution was drafted.
Although Article VII of the Constitution stated that ratification by only nine states was required, the new government did not begin the process of organizing itself and setting up elections until a total of 11 states had voted to ratify. New York was the 11th state to vote to ratify in July 1788. The next state to ratify was North Carolina, 1 year and 4 months later in November 1789.