New Hampshire became the ninth state to ratify the U.S. Constitution, allowing it to take effect.
Article Seven required approval from nine of the thirteen states before the Constitution could become the nation’s governing framework. New Hampshire’s ratifying convention approved it on June 21, 1788, reaching that threshold.
The vote was close: 57 delegates supported ratification and 47 opposed it. New Hampshire’s decision came after South Carolina became the eighth state and before Virginia became the tenth.
This milestone is sometimes confused with the Constitution’s operational start date. The ninth ratification established the Constitution, but the new federal government began operating under it on March 4, 1789. Rhode Island was the final original state to ratify, doing so in 1790.