Washington D.C., also know as the District of Columbia, is the capital of the the United States. The name Washington was in honor of the first president, George Washington, and the Columbia was in reference to Christopher Columbus. The city itself was founded in 1790, and George Washington chose the site in 1791. It was designed by the French architect Pierre Charles L'Enfant, and was the first American city to be planned with a specific purpose. It was intended to be a beautiful city with wide streets and many trees, and the city's business was to be centered around the government.
It became the nation's capital on June 11, 1800. Before that, the country had been governed from Philadelphia, Pennsylvania. Washington D.C. is located on the Potomac River, surrounded by the states of Maryland and Virginia. Some of the government buildings located there are the White House, the Capitol Building, the Supreme Court, and many more.