The Constitution of the United States of America is the supreme law of the United States. It is the foundation and source of the legal authority underlying the existence of the United States of America and the Federal Government of the United States. It provides the framework for the organization of the United States Government and for the relationship of the Federal government to the States, to citizens, and to all people within the United States.
The Constitution defines the three main branches of government: a legislature, bicameral Congress; an executive branch led by the President; and a judicial branch headed by the Supreme Court. The Constitution outlines the powers and duties of each branch. The Constitution reserves numerous powers for the states, thereby establishing the federal system of government.
The United States Constitution was adopted on September 17, 1787, by the Constitutional Convention in Philadelphia, Pennsylvania, and ratified by conventions in each U.S. state in the name of "The People". The Constitution has been amended twenty-seven times; the first ten amendments are known as the Bill of Rights.
The United States Constitution is the shortest and oldest written constitution in the world.
The Constitution has a central place in United States law and political culture. The handwritten, or "engrossed", original document penned by Jacob Shallus is on display at the National Archives and Records Administration in Washington, D.C.