The Battle of Fort Donelson Summary & Facts | Civilwar.org

On Feb. 13, 1862 – The four day Battle of Fort Donelson, Tennessee, begins. After capturing Fort Henry on February 6, 1862, Grant advanced cross-country to invest Fort Donelson. The original garrison of the two forts was about 2,500 men, and Albert Johnston had dispatched about 12,000 reinforcements from Bowling Green, KY, under John Floyd to bolster the defense. A few men also arrived from Columbus, the western end of the Confederate defensive line. Grant had wanted to move fast, to prevent reinforcements arriving at all, but wretched weather (rain before and during his operations ruined the roads) delayed him and the Confederate troops arrived safely. Fort Donelson was a much stronger work than Fort Henry, larger, with a stronger garrison, about 100 feet above the river (so it had plunging fire on ships), and on a ridge which narrowed routes for infantry attack. The Confederates had a strong line on the next ridge outwards from the fort, with each of the Generals commanding a sector while Floyd (the senior) also had overall command. Grant deployed two divisions in line, with a third arriving. On the 12th, despite orders not to, McClernand had one of his brigades probe the Confederate defenses. They charged two or three times and found the defenses strong and well manned: Union losses were heavy. Grant had intended simply to surround the fort and have the Navy batter it into submission.