The United States Constitution is the supreme law of the United States of America. It provides the framework for the organization of the United States Government. The document outlines the three main branches of the government. The executive branch is headed by the President. The legislative branch is embodied in the bicameral Congress. The judicial branch is headed by the nine-member Supreme Court. Besides providing for the organization of these branches, the Constitution carefully outlines which powers each branch may exercise. It also reserves numerous rights for the individual states, and thus establishes the United States' federal system of government.

The United States Constitution was adopted on September 17 1787, by the Constitutional Convention in Philadelphia, Pennsylvania, and later ratified by conventions in each state in the name of "the People"; it has since been amended twenty-seven times, the first ten ammendments being known as the Bill of Rights. The Constitution has a central place in United States law and political culture. The U.S. Constitution is the oldest federal constitution of any existing nation. The handwritten, or "engrossed", original document is on display at the National Archives and Records Administration in Washington, D.C. The United States Constitution has 4,543 words, including the signatures.