During the American Civil War, Washington, D.C. was the most heavily fortified city in North America. As President Abraham Lincoln's Capital, the city became the symbol of Union determination, as well as a target for Robert E. Lee's Confederates. As a Union army and navy logistical base, it contained a complex of hospitals, storehouses, equipment repair facilities, and animal corrals. These were in addition to other public buildings, small urban areas, and vast open space that constituted the capital on the Potomac. To protect Washington with all it contained and symbolized, the Army constructed a shield of fortifications: 68 enclosed earthen forts, 93 supplemental batteries, miles of military roads, and support structures for commissary, quartermaster, engineer, and civilian labor force, some of which still exist today. Thousands of troops were held back from active operations to garrison this complex. And the Commanders of the Army of the Potomac from Irvin McDowell to George Meade, and informally U.S. Grant himself, always had to keep in mind their responsibility of protecting this city, at the same time that they were moving against the Confederate forces arrayed against them. Revised in style, format, and content, the new edition of Mr. Lincoln's Forts is the premier historical reference and tour guide to the Civil War defenses of Washington, D.C.