Washington, D.C., often referred to as the capital of the United States, is located in the District of Columbia, a federal district created by Congress. This city serves as the political and administrative center of the nation, housing the White House, the U.S. Capitol, and numerous federal agencies. The city's strategic location in the Mid-Atlantic region makes it easily accessible to major cities along the East Coast.

The decision to establish Washington, D.C., as the nation's capital was made during the Constitutional Convention of 1787. The city was chosen for its central location between the original 13 states, ensuring that no single state would have undue influence over the federal government. The city's design was influenced by the neoclassical architecture of ancient Greece and Rome, with wide streets and grand public buildings.

According to the U.S. Census Bureau, as of 2020, the population of Washington, D.C., was approximately 704,000 residents. This population includes a diverse mix of ethnicities and backgrounds, contributing to the city's vibrant cultural scene. The city's economy is primarily driven by the federal government, with significant contributions from the service and technology sectors.

Washington, D.C., is renowned for its rich history and political significance. The National Mall, a 1-mile-long, 300-foot-wide park, is a national landmark that houses iconic monuments and memorials, including the Lincoln Memorial, the Washington Monument, and the Vietnam Veterans Memorial. The city also hosts numerous museums and galleries, such as the Smithsonian Institution, which is the world's largest museum, education, and research complex.

The city's strategic location and historical significance make it a hub for international diplomacy. The United Nations headquarters in New York City, although not located in Washington, D.C., is a major international organization with a significant presence in the city. Additionally, Washington, D.C., is home to numerous embassies and international organizations, making it a global center for politics and international relations.

In conclusion, Washington, D.C., is the capital of the United States, serving as the political and administrative center of the nation. Its central location, rich history, and cultural diversity make it a significant city both domestically and internationally.