Which state became the ninth to ratify the U.S. Constitution?

New Hampshire became the ninth state to ratify the U.S. Constitution.

New Hampshire’s convention approved ratification on June 21, 1788. The vote was decisive because Article VII required nine states to ratify the Constitution before it could establish the new federal government among the approving states.

The convention initially met in February 1788 but adjourned without reaching agreement. It reconvened in June after supporters and opponents negotiated amendments and assurances. New Hampshire’s approval followed ratification by Delaware, Pennsylvania, New Jersey, Georgia, Connecticut, Massachusetts, Maryland, and South Carolina.

Virginia and New York ratified soon afterward, while North Carolina and Rhode Island held out longer. The Bill of Rights was proposed in 1789 partly in response to concerns raised during the ratification debates. New Hampshire’s vote therefore marked both a constitutional turning point and a major step toward the government that began operating in 1789.