Leesburg was a regional transportation hub. It was the northwestern terminus of the Alexandria, Loudoun & Hampshire Railroad which ran along or near the Potomac River from Alexandria, Virginia which is across the river from Washington, D.C. Johnston, II, Angus James. Virginia Railroads in the Civil War. Chapel Hill, NC: The University of North Carolina Press, 1961. OCLC977752. p. 93. Control of the nearby fords and ferries was the key to controlling north or south invasion routes. Meserve, Stevan F. The Civil War in Loudoun County, Virginia: A History of Hard Times. With a Chapter on Ball's Bluff by James A. Morgan, III. Charleston, SC: The History Press, 2008. ISBN978-1-59629-378-6. p. 31.