In what year was the Constitution ratified?

The Constitution of the United States was ratified in 1788, with the process beginning after it was drafted in 1787 during the Constitutional Convention in Philadelphia. The significant event of ratification occurred when the ninth state, New Hampshire, ratified the Constitution on June 21, 1788. This allowed the Constitution to take effect, although many states proposed amendments, leading to the Bill of Rights' adoption in 1791. The ratification in 1788 solidified the framework of the government as outlined in the Constitution, making it the correct choice for this question. Understanding the timeline of these events is critical in grasping the foundational legislative history of the United States.