On September 1787, Congress directed the state legislatures to call ratification conventions in each state. Article VII stipulated that nine states had to ratify the Constitution for it to go into effect.
• Delaware - December 7, 1787.
• Pennsylvania - December 12, 1787.
• New Jersey - December 18, 1787.
• Georgia - January 2, 1788.
• Connecticut - January 9, 1788.
• Massachusetts - February 6, 1788.
• Maryland - April 28, 1788.
• South Carolina - May 23, 1788.
• New Hampshire – June 21, 1788
The Constitution was officially adopted by the United States when it was ratified by New Hampshire on June 21, 1788, the ninth state to do so