United States

Washington, D.C. is the capital of the United States because the Residence Act of 1790 established a special federal district—independent of any state—along the Potomac River to house the national government. Since 1800, it has been the seat of the three branches: the White House (executive), the U.S. Capitol (legislative), and the Supreme Court (judicial). “D.C.” stands for District of Columbia. New York City, Los Angeles, and Chicago are major economic and cultural centers, but they are not where the federal government is based. Memory tip: the capital (city) contains the Capitol (building with the dome). Or think “Decisions in D.C.”—that’s where national laws are made and the president lives.