Washington D.C., Became the Capital. Where are the White House, the Capitol, and the Washington Monument? Just where they should be--in the capital of the United States. On July 16, 1790, Congress declared the city of Washington in the District of Columbia, the permanent capital of the United States.
Washington, DC became the national capital because the southerners thought that the capital being in New York gave the northern states to much influence over national policy. The capital of the United States was then moved to Washington, DC after being in Philadelphia for 10 years. I hope that helps.
