December 12, 1800 - Washington D.C. Established as U.S. Capital
Washington, D.C. is officially recognized as the capital of the United States. Article 1, Section 8, Clause 17 of the U.S. Constitution authorizes establishment of a federal district not to exceed 10 miles square. Chosen by George Washington and situated along the banks of the Potomac River, the permanent capital is designed by French-born American architect Pierre L'Enfant. Upon its completion, the seat of government is transferred from Philadelphia and President John Adams takes up residence in the White House.