Growing shortages in the number of personnel after the Mexican War stretched the resources of the U.S. Army. At Fort Washington (see drawing at left), as at many other posts, the garrison was withdrawn leaving only a skeleton maintenance staff. As sectional differences increased and the country moved closer to the horror of civil war, Fort Washington found itself in a precarious position: near the Nation's Capital and across the river from the most populous slave state.
By February 1861, after South Carolina and six other states had declared their independence from the United States, the possibility loomed that Virginia would also secede, making the fort's geographic position critical. Other observers saw a threat from the southern sympathizers residing in Prince Georges County, Md., where the fort was located.
On January 1, 1861, Secretary of the Navy Isaac Toucey issued an order for the defense of the capital. The task of putting the defenses in order fell to an Army engineer officer, Lt. George Washington Custis Lee, son of Col. Robert E. Lee. By early May 1861 both Lees would resign their commissions in the U.S. Army and offer their services to their home state, Virginia.
Forty Marines under command of Capt. Algernon S. Taylor were assigned to Fort Washington, at that time the only fortification near the city. Taylor feared that the 40 Marines were not enough and asked for reinforcements. On January 26, 1861 , a company of U.S. Army recruits were relieved the Marines. On April 15, the day after Fort Sumter surrendered in Charleston harbor, the War Department sent the 1st U.S. Artillery to Fort Washington. It was commanded by Capt. Joseph A. Haskin (left), who had arrived in Washington from Baton Rouge, La., where he had been forced to surrender the federal arsenal and barracks to local secessionists earlier in the year.
For a time Fort Washington was the only defense for the national capital, and it was vitally important, for it controlled movement on the river. Quickly, however, Maj. Gen. John G. Barnard of the Corps of Engineers directed the building of a string of 68 enclosed earthen forts and batteries to protect all approaches to Washington. By the end of the war, 20 miles of rifle pits and more than 30 miles of military roads encircled the city. Remnants of some of these defenses can still be seen today.