Rhode Island was the last state to ratify the United States Constitution.
Rhode Island rejected the Constitution in a popular referendum in March 1788 and declined to send delegates to the Philadelphia Convention. Critics there feared that the proposed federal government would become too powerful and objected to the absence of a bill of rights in the original document.
After the Constitution took effect, Rhode Island held a ratifying convention in 1790. On May 29, the state approved the Constitution by a vote of 34 to 32, becoming the thirteenth and final state to join the constitutional union.
New Hampshire had already become the decisive ninth state in June 1788, allowing the new government to proceed. North Carolina ratified in November 1789, while Rhode Island waited until 1790.