In what year was the U.S. Constitution ratified?

The correct year for the ratification of the U.S. Constitution is 1788. This was the year when the Constitution was officially ratified after being adopted by the Constitutional Convention in 1787. The final state needed for ratification, New Hampshire, approved it on June 21, 1788, thus bringing the number of ratifying states to nine, which was the minimum required for the Constitution to take effect. Although the Constitution was drafted in 1787, it was not until the following year that it was ratified and began to govern the United States. This makes 1788 the pivotal year in which the framework of the new government was formally accepted and set into motion.