On September 17, 1787, the United States Constitution was officially signed by 39 of the 55 delegates at the Constitutional Convention in Philadelphia, Pennsylvania. Less than one year later the states ratified the Constitution and it became the supreme law of the United States.

For around four months in 1787 the delegates met daily at the State House (now called Independence Hall) in Philadelphia, Pennsylvania to revise the Articles of Confederation and come up with a new federal constitution. James Madison acted as one of the most influential delegates and took studious notes of the proceedings to the point of utter exhaustion.

In the months following the approval of the Constitution by the delegates, Madison, Alexander Hamilton, and John Jay wrote numerous letters called The Federalist Papers to the people in support of passing the new Constitution. Other influential individuals opposed the new Constitution including Patrick Henry, George Mason, and Elbridge Gerry. These men argued that the new Constitution gave too much power to the federal government and did not retain enough power for the states. However, the tide for the new Constitution eventually won and was ratified by the states.

Today, the Constitution acts as the foundation for all U.S. legal authority. It provides the framework for how the United States government works, including the relationship of the three branches of government, federal government with the states, and many of the natural rights given to the citizens.

The U.S. Constitution is currently the shortest and oldest written constitution still in use by any county in the world.