What is the capital of the United States?

Washington, D.C. is the capital of the United States because it was established as the seat of the federal government by the Constitution. The city serves not only as the political center of the country but also houses important national landmarks, including the White House, the Capitol, and the Supreme Court. As the capital, it plays a crucial role in the governance and administration of federal laws, policies, and operations.

The other cities mentioned, such as New York City, Chicago, and Los Angeles, while significant in terms of culture, economy, and population, do not serve the role of the federal capital and therefore do not house the key national governmental institutions that define the capital status.