The Battle of Fort Donelson was fought from the 11th to the 16th of February, 1862 in the Western Theatre of the American Civil War. The battle was fought immediately after the surrender of Fort Henry, Tennessee on February 6th, 1862. The Confederates’ lateral mobility in moving reinforcements into their territory to offer defense against the larger Union forces had already been restricted, as the Union troops had cut the railroad supply lines south of Fort Henry in the days following the surrender of the fort. The Confederates therefore had no choice but to surrender the fort and, since a great number of their defenders had already marched to Fort Donelson, this second fort in the area was therefore poised to become the next battleground between Grant’s troops and the belligerent Confederates. Splintered divisions would later occur among the Confederates, as Grant’s army split them right down the middle. It was on February the 6th when Grant openly declared his wish to attack Fort Donelson in a wire to his superior, the Commander of the Department of the Missouri, Major General Henry W. Halleck. In the wire, he confidently proclaimed that he would capture Fort Donelson just as he had Fort Henry.
The major opposing forces were the Union and the Confederates. The Union was commanded by Grant, and it consisted of three major divisions that were commanded by Brigadier Generals C. F. Smith, John McClernard, and (last-minute appointee) Lew Wallace. The infantry divisions were supported by two regiments of cavalry as well as eight batteries of artillery. The Western Gunboat Flotilla, under Flag Officer Andrew H. Foote, additionally contributed 4 ironclad gunboats, as well as 3 timber clad gunboats, to the Union efforts. On the other hand, the Confederate force of about 1,700 men was comprised by 3 infantry divisions and garrison troops, as well as attached cavalry. The combined forces were under the command of Brigadier General John B. Floyd. The 3 individual divisions were under the respective commands of Floyd (who was later replaced by the Colonel Gabriel C. Wharton due to the fact that Floyd took charge of the whole force), Brigadier General Simon Bolivar Buckner, and the northern-born Brig. Gen. Bushrod Johnston.
The Battle of Fort-Donelson resulted in 507 deaths, 1,976 wounded, and 208 captured or missing among the Union's forces, and 327 deaths, 1,127 wounded, and 12,392 captured or missing Confederate soldiers. Combining both sides, more than 3,000 were wounded in the field of battle, and a snowstorm and cold temperatures worsened the situation for all parties involved. The captured troop totals at Fort Donelson were massive, largely because of the surrender by the large Confederate force. When the Confederates eventually asked for terms of surrender, Grant replied that no terms “except unconditional and immediate surrender” would be acceptable, consequently earning him his nickname “Unconditional Surrender” Grant, in lieu of these terms and his actual initials.
All in all, the losses of Fort Henry and Fort Donelson were disastrous for the Confederates, and worsened the state of their logistical and tactical positions in the Western Theater for the remainder of the war. Kentucky and most of Tennessee were then under Union military control, and diminished Confederate threats to Ohio, Indiana, Illinois, and Missouri. The weakened state of the Army of Tennessee was a major factor in the Confederate defeat in the Battle of Shiloh, Tennessee around 2 months later. The Fort Donelson National Battlefield and its cemetery have been preserved and protected by the National Park Service for more than 80 years now, and attract hundreds of thousands of visitors every year. The graveyard contains both Union troops from the Civil War and those from later wars, though it is at this time not offering additional veteran burial sites.