Adam Badeau, Military history of Ulysses S. Grant from April 1861 to April 1865. Volume 1

[23] threatening northern Kentucky and protecting Nashville and middle Tennessee. At the centre of this important strategic line, the Tennessee and Cumberland rivers formed the natural avenues into all the disputed territory north of the cotton states. About fifty miles from the Ohio, and near the boundary between Kentucky and Tennessee, these two great streams approach within twelve miles of each other, and here, at a bend in each river, the rebels had erected their strongholds. Fort Henry, on the Tennessee, and Fort Donelson, on the Cumberland, completely commanded the navigation, and stood like great barred gateways against any advance of the national armies. Their sites had been selected with care; they had been elaborately fortified, and large garrisons were stationed to defend them. They covered the great railroad line of communication from east to west, through the border states, and their possession determined the fate of Kentucky and Tennessee; for Nashville and Memphis were not fortified, and Bowling Green and Columbus would both be turned, whenever the national arms subdued these forts.

The battle of Belmont was fought on the 7th of November, and on the 9th, Major-General Henry W. Halleck, superseding Fremont, took command of the new Department of the Missouri, including Arkansas and the portion of Kentucky west of the Cumberland. The Department of the Ohio, consisting of that part of Kentucky east of the Cumberland, and the state of Tennessee, as well as certain portions of the loyal states, was assigned to Brigadier-General Don Carlos Buell, with headquarters at Louisville.

In all the operations at the West, during the first