I INTRODUCTION   Washington, D.C., city and district, capital of the United States of America. The city of Washington has the same boundaries as the District of Columbia (D.C.), a federal territory established in 1790 as the site of the new nation’s permanent capital. Named after the first U.S. president, George Washington, the city has served since 1800 as the seat of federal government. It is also the heart of a dynamic metropolitan region. During the 20th century, the Washington, D.C., metr...