including the states of Virginia, West Virginia, Maryland, and Pennsylvania, the District of Columbia, and the coastal fortifications and seaports of North Carolina. Background Army of the Potomac Maj. Gen. George B. McClellan took command of the Union Army of the Potomac on July 26, 1861 (he was briefly general-in-chief of all the Union armies, but was subsequently relieved of that post in favor of Maj. Gen. Henry W. Halleck), and the war began in earnest in 1862. The 1862 Union strategy called for simultaneous advances along four axes: McClellan would lead the main thrust in Virginia towards Richmond. Ohio forces would advance through Kentucky into Tennessee. The Missouri Department would drive south along the Mississippi River. The westernmost attack would originate from Kansas. Army of Northern Virginia The primary Confederate force in the Eastern theater was the Army of Northern Virginia. The Army originated as the (Confederate) Army of the Potomac, which was organized on June 20, 1861, from all operational forces in Northern Virginia. On July 20 and 21, the Army of the Shenandoah and forces from the District of Harpers Ferry were added. Units from the Army of the Northwest were merged into the Army of the Potomac between March 14 and May 17, 1862. The Army of the Potomac was renamed Army of Northern Virginia on March 14. The Army of the Peninsula was merged into it on April 12, 1862. When Virginia declared its secession in April 1861, Robert E. Lee chose to follow his home state, despite his desire for the country to remain intact and an offer of a senior Union command. Lee's biographer, Douglas S. Freeman, asserts that the army received its final name from Lee when he issued orders assuming command on June 1, 1862. However, Freeman does admit that Lee corresponded with Brigadier General Joseph E. Johnston, his predecessor in army command, before that date and referred to Johnston's command as the Army of Northern Virginia. Part of the confusion results from the fact that Johnston commanded the Department of Northern Virginia (as of October 22, 1861) and the name Army of Northern Virginia can be seen as an informal consequence of its parent department's name. Jefferson Davis and Johnston did not adopt the name, but it is clear that the organization of units as of March 14 was the same organization that Lee received on June 1, and thus