The Union military command in the West, however, suffers from a lack of unified command, organized by November into three separate departments: the Department of Kansas, under Major General David Hunter, the Department of the Missouri, under Major General Henry Halleck, and the Department of the Ohio, under Brigadier General Don Carlos Buell (who had replaced Brigadier General William Tecumseh Sherman).

By January 1862, this disunity of command is apparent because no strategy for operations in the Western theater can be agreed upon.

Buell, under political pressure to invade and hold pro-Union East Tennessee, moves slowly in the direction of Nashville, but achieves nothing more substantial toward his goal than minor victories at Middle Creek (January 10, 1862) under Colonel James A. Garfield and Mill Springs (January 19) under Brig. Gen. George Henry Thomas. (Mill Springs is a significant victory in a strategic sense because it breaks the end of the Confederate Western defensive line and opens the Cumberland Gap to East Tennessee, but it gets Buell no closer to Nashville.)

General Don Carlos Buell, under political pressure to invade and hold pro-Union East Tennessee, moves slowly in the direction of Nashville, but achieves nothing more substantial toward his goal than minor victories at Middle Creek (January 10, 1862) under Colonel James A. Garfield and Mill Springs (January 19) under Brigadier General George Henry Thomas. (Mill Springs is a significant victory in a strategic sense because it breaks the end of the Confederate Western defensive line and opens the Cumberland Gap to East Tennessee, but it gets Buell no closer to Nashville.)