There were original 13 states that ratified the United States Constitution to join the Union. They formally approved and accepted the United States Constitution.
The list of states and their respective dates of ratification to join the Union are as follows.
- 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
- Virginia - June 25, 1788
- New York - July 26, 1788
- North Carolina - November 21, 1789
- Rhode Island - May 29, 1790