Delaware became the first state to ratify the U.S. Constitution, approving it unanimously on December 7, 1787.
Delaware’s ratifying convention voted 30–0, earning the state its enduring nickname, “The First State.” Its action came less than three months after the Constitutional Convention signed the proposed Constitution in Philadelphia.
Article Seven specified that the Constitution would take effect among the states once nine states ratified it. New Hampshire became the ninth state on June 21, 1788, making the Constitution operative for the participating states.
Delaware’s early approval did not mean every state agreed quickly. Pennsylvania followed five days later, but Rhode Island waited until May 29, 1790, becoming the last of the original 13 states to ratify. Delaware had also been one of the original states that joined the American Revolution.