Sixty proof sheets of the Constitution of the United States are delivered to the Constitutional Convention in Philadelphia, Pennsylvania.

The Constitution of the United States is the supreme law of the United States of America. It superseded the Articles of Confederation, the nation's first constitution, on March 4, 1789. Originally including seven articles, the Constitution delineates the frame of the federal government. The Constitution's first three articles embody the doctrine of the separation of powers, in which the federal government is divided into three branches: the legislative, consisting of the bicameral Congress ; the executive, consisting of the president and subordinate officers ; and the judicial, consisting of the Supreme Court and other federal courts. Article IV, Article V, and Article VI embody concepts of federalism, describing the rights and responsibilities of state governments, the states in relationship to the federal government, and the shared process of constitutional amendment. Article VII establishes the procedure subsequently used by the 13 states to ratify it. The Constitution of the United States is the oldest and longest-standing written and codified national constitution in force in the world.

The Constitutional Convention took place in Philadelphia from May 25 to September 17, 1787. While the convention was initially intended to revise the league of states and devise the first system of federal government under the Articles of Confederation, leading proponents of the Constitutional Convention, including James Madison of Virginia and Alexander Hamilton of New York, sought to create a new frame of government rather than revise the existing one. Delegates elected George Washington of Virginia, former commanding general of the Continental Army in the American Revolutionary War and a proponent of a stronger national government, to serve as president of the convention. The convention ultimately debated and ratified the Constitution of the United States, making the convention one of the most significant events in American history.

Philadelphia, colloquially referred to as Philly, is the most populous city in the U.S. state of Pennsylvania. It is the sixth-most populous city in the United States with a population of 1.6 million at the 2020 census, while the Philadelphia metropolitan area with 6.33 million residents is the nation's ninth-largest metropolitan area. Philadelphia is known for its culture, cuisine, and history, maintaining contemporary influence in business and industry, culture, sports, and music.