Delaware ratified the U.S. Constitution by a unanimous vote of 30–0 in 1787.
Delaware’s ratifying convention approved the Constitution on December 7, 1787. This made Delaware the first state to ratify the new governing document, earning it the enduring nickname “The First State.”
The vote took place under Article Seven, which required approval from conventions in at least nine of the thirteen states for the Constitution to take effect. Delaware’s unanimous decision was followed by Pennsylvania five days later.
The Constitution ultimately received the required ninth ratification from New Hampshire on June 21, 1788. Rhode Island was the last of the original thirteen states to ratify, doing so on May 29, 1790, by a much narrower 34–32 vote.