Maj. Gen. George B. McClellan took command of the Union Army of the Potomac on July 26, 1861, and the war began in earnest in 1862. The 1862 Union strategy called for simultaneous advances along four axes:

1. McClellan would lead the main thrust in Virginia towards Richmond.
2. Ohio forces would advance through Kentucky into Tennessee.
3. The Missouri Department would drive south along the Mississippi River.
4. The westernmost attack would originate from Kansas.