when was the constitution adopted

The United States Constitution was signed by delegates on September 17, 1787, at the Constitutional Convention in Philadelphia. It then went to the states for ratification, requiring nine of the thirteen states to approve it before it became the official framework of the government. This threshold was reached on June 21, 1788, when New Hampshire became the ninth state to ratify the Constitution. This ratification officially ended the government under the Articles of Confederation and adopted the Constitution as the governing document of the United States. The new government under the Constitution began operation on March 4, 1789. All thirteen states had ratified the Constitution by May 29, 1790.