Washington, D.C., became the permanent capital of the United States when the federal government moved there in 1800.
The 1790 Residence Act authorized a federal district along the Potomac River. President George Washington selected the site, and engineer Pierre Charles L'Enfant prepared an influential plan for the new capital. The district was named for Washington, while the city was named after him as well.
The national government first operated under the Constitution in New York City. It moved to Philadelphia in 1790 and remained there for a decade while the federal district was being developed. Congress held its first session in Washington on November 17, 1800, in the unfinished Capitol.
Washington, D.C., is a federal district rather than a state. The abbreviation D.C. means District of Columbia, a name honoring Christopher Columbus. The city is often called Washington, but using the full name helps distinguish it from the state of Washington on the Pacific coast.