From Wikipedia

More Sex In The Civil War

As capital of the United States, the federal district of Washington, D.C., became a significant civilian leadership, military headquarters, and logistics center during the American Civil War. Defending the capital became a major priority of the War Department, and often dictated military strategy. In many ways, the war transformed Washington from a rather modest semi-rural city into the urban center of American federalism, as population, government, infrastructure, public and private buildings, and visitation all dramatically increased during the conflict, setting the stage for the rapid expansion of the city throughout the latter half of the 19th century.