What is the capital of the United States?

Washington, D.C. is the capital of the United States because it was specifically chosen to serve as the seat of the federal government. Established by the Constitution, Washington, D.C. is located along the Potomac River and is home to key government institutions such as the White House, the Capitol Building, and the Supreme Court. The decision to create a separate federal district was intended to ensure that no single state would have undue influence over the national government.

The other choices, such as New York City, Los Angeles, and Chicago, are major cities in the U.S. but do not serve the political functions of the nation's capital. New York City was briefly the capital of the U.S. in the late 18th century, but the capital moved to Philadelphia before being established in Washington, D.C. in 1800. Each of these cities has its own unique significance and role in the history and development of the country, but none holds the official status of the capital.