The Battle of Fort Donelson was a battle in the American Civil War.

In February 1862, Union general Ulysses S. Grant advanced south along the Tennessee River with gunboats and more than 15,000 troops. His objective was to take Fort Henry and Fort Donelson which protected the importnat Tennessee and Cumberland rivers. After forcing Fort Henry to surrender, Grant attacked Fort Donelson shelling the fort for three days from February 11 to 16. On February 16, 1862, after the failure of their all-out attack aimed at breaking through Grant’s investment lines, the fort’s 12,000-man garrison surrendered unconditionally. This was a major victory for Brig. Gen. Ulysses S. Grant and a catastrophe for the South. It ensured that Kentucky would stay in the Union and opened up Tennessee for a Northern advance along the Tennessee and Cumberland rivers. Grant received a promotion to major general for his victory and attained stature in the Western Theater, earning the nom de guerre “Unconditional Surrender.” There were 17,398 total casualties (US 2,331; CS 15,067) .

Principal Commanders: Brig. Gen. Ulysses S. Grant and Flag-Officer A.H. Foote [US]; Brig. Gen. John B. Floyd, Brig. Gen. Gideon Pillow, and Brig. Gen. Simon B. Buckner [CS]