A decisive Union victory in the American Civil War where General Ulysses S. Grant captured the Confederate stronghold Fort Donelson, leading to the surrender of approximately 12,000 Confederate soldiers and securing Union control of Kentucky and Tennessee.

The Battle of Fort Donelson stands as one of the pivotal engagements of the American Civil War. Fought between February 11-16, 1862, this crucial battle marked the Union's first major victory in the Western Theater and launched the career of Union General Ulysses S. Grant.

Located on the Cumberland River in Tennessee, Fort Donelson served as a critical Confederate stronghold protecting Nashville and the South's heartland. The battle resulted in a decisive Union victory when approximately 12,000 to 13,000 Confederate soldiers surrendered to Grant's forces. This historic event earned Grant his famous nickname "Unconditional Surrender" Grant and helped secure Union control of Kentucky and much of Tennessee.

Fort Donelson's location on the Cumberland River created a vital defensive position for controlling river traffic in Tennessee. The fort sat atop a 100-foot bluff overlooking the river, providing strategic advantages for artillery placement and surveillance of enemy movements.

The Confederate stronghold formed part of a defensive line that included:

• Fort Henry on the Tennessee River
• Fort Heiman across from Fort Henry
• Fort Donelson on the Cumberland River

The fort's strategic value stemmed from multiple tactical advantages:

1. River Control

• Blocked Union gunboat access to Nashville
• Protected Confederate shipping routes
• Controlled commercial traffic on the Cumberland River
• Secured supply lines for Confederate forces

1. Geographic Position

• Protected Nashville from Union advances
• Secured Tennessee's industrial resources
• Connected Confederate positions in Kentucky
• Maintained railway access to the South

The fort's defensive infrastructure enhanced its strategic value:

• 15 heavy artillery pieces facing the river
• 2 miles of outer earthwork defenses
• 12 infantry regiments stationed inside
• Multiple artillery batteries on the hillsides

Fort Donelson's Defensive Statistics	Numbers
Total Garrison Size (1862)	17,000 troops
Artillery Pieces	42 guns
Fortress Area	100 acres
River Frontage	1 mile

The fort's position created a defensive barrier that protected Confederate territories from Union advances through Kentucky into Tennessee. Its capture opened Nashville to Union forces and compromised Confederate control throughout the region.

The Union campaign against Fort Donelson began on February 11, 1862, following the successful capture of Fort Henry on the Tennessee River. Union forces under General Ulysses S. Grant initiated a coordinated land and naval assault to secure this strategic Confederate stronghold.

Grant's army of 25,000 men marched 12 miles east from Fort Henry to Fort Donelson on February 12-13. The Union forces established positions around the Confederate fortifications in a semicircular formation:

• The 1st Division under McClernand secured the right flank

• The 2nd Division led by Smith positioned on the left

• The 3rd Division under Wallace formed the center

• Three brigades of reinforcements arrived on February 14, bringing total Union strength to 27,000

• 4 ironclad gunboats (USS St. Louis, USS Carondelet, USS Louisville USS Pittsburgh)

• 2 wooden gunboats (USS Conestoga USS Tyler)

• Confederate shore batteries severely damaged 3 gunboats

• USS St. Louis took 59 direct hits

• USS Louisville lost steering control

• Union naval forces withdrew after 90 minutes of intense fire

Naval Forces	Union Vessels	Confederate Artillery Hits
Ironclads	4	59+ hits on USS St. Louis
Wooden Gunboats	2	Multiple direct hits
Duration	90 minutes	N/A

The Battle of Fort Donelson unfolded over three intense days from February 13-15, 1862, marking a critical turning point in the Western Theater of the Civil War. The battle demonstrated the increasing sophistication of Union military operations combining land and naval forces.

Union forces initiated the engagement with probing attacks against Confederate positions. The 1st Division under General McClernand secured positions on the Confederate right while General C.F. Smith's 2nd Division established control of the Union left flank. Confederate artillery from the fort's elevated positions responded with precise fire, inflicting 126 Union casualties during these initial skirmishes.

Flag Officer Andrew Foote led six Union gunboats in a concentrated attack on Fort Donelson's river batteries at 3:00 PM. The Confederate shore batteries, armed with 12 heavy guns, damaged all four ironclad vessels in the assault:

Gunboat	Damage Sustained
USS St. Louis	8 direct hits
USS Carondelet	54 hits, steering damaged
USS Louisville	Steering disabled
USS Pittsburgh	20 hits, forced withdrawal

Confederate forces launched a dawn attack at 6:30 AM with 10,000 troops against the Union right wing. General Pillow's division initially succeeded in pushing back McClernand's forces 1 mile, creating an escape corridor toward Nashville. Grant's afternoon counterattack, spearheaded by General C.F. Smith's division scaling the Confederate right with 2,000 men, recaptured the lost ground. The failed breakout attempt led to Confederate generals Floyd, Pillow transferring command to General Buckner, who requested surrender terms from Grant.

The Confederate surrender at Fort Donelson occurred on February 16, 1862, marking a significant turning point in the American Civil War. The surrender involved approximately 12,000-13,000 Confederate troops, making it the largest capture of Confederate forces in the war up to that time.

Confederate Generals John B. Floyd and Gideon J. Pillow orchestrated their escape from Fort Donelson during the night of February 15-16, 1862. Floyd, a former U.S. Secretary of War under President Buchanan, transferred command to Pillow who then passed it to General Simon Bolivar Buckner. Floyd escaped with 1,500 troops across the Cumberland River in two small steamers, while Pillow crossed in a small boat with his staff. Colonel Nathan Bedford Forrest led his cavalry force of 700 men through shallow water and escaped eastward.

Confederate Leaders	Number of Troops Escaped
General Floyd	1,500
Colonel Forrest	700

• Immediate transfer of all weapons and military supplies to Union forces
• Complete cessation of Confederate resistance
• Transfer of all Confederate soldiers to Union prisoner-of-war camps
• Surrender of all Confederate officers' personal arms and equipment

The Battle of Fort Donelson transformed the strategic landscape of the Western Theater in 1862. Its capture by Union forces reshaped both territorial control and military leadership dynamics during the American Civil War.

The Union victory at Fort Donelson secured control of the Cumberland River transportation network. This strategic advantage opened Middle Tennessee to Union forces, leading to the capture of Nashville on February 25, 1862. The Confederate loss of the Tennessee River systems created these impacts:

• Disrupted Confederate supply lines between the Upper South and Deep South
• Enabled Union gunboats to operate freely along 200 miles of river channels
• Provided Union forces with reliable transportation routes for troops and supplies
• Cut off vital Confederate railroad connections in Tennessee and Kentucky

River Control Impact	Before Battle	After Battle
Miles of River Controlled by Union	0	200
Major Ports Under Union Control	0	3
Confederate Supply Routes Blocked	0	4

• Earned Grant promotion to Major General
• Generated widespread Northern media coverage of Grant's military prowess
• Established Grant's reputation for aggressive tactical operations
• Created public confidence in Union military leadership
• Demonstrated Grant's skill in coordinating infantry and naval forces

Grant's Career Impact	Before Fort Donelson	After Fort Donelson
Military Rank	Brigadier General	Major General
Troops Under Command	15,000	48,000
Territory Controlled (sq. miles)	50	250

• The Battle of Fort Donelson took place from February 11-16, 1862, marking the Union's first major victory in the Western Theater of the Civil War
• Fort Donelson's strategic location on the Cumberland River in Tennessee made it a crucial Confederate stronghold, protecting Nashville and controlling vital river traffic
• The battle ended with the surrender of approximately 12,000-13,000 Confederate soldiers to Union forces led by General Ulysses S. Grant
• The victory earned Grant his nickname "Unconditional Surrender" Grant and led to his promotion to Major General
• The capture of Fort Donelson opened up the Cumberland River to Union control, eventually leading to the fall of Nashville and Union dominance in Tennessee

The Battle of Fort Donelson stands as a pivotal moment that reshaped the American Civil War's trajectory in early 1862. The Union's triumph not only secured vital waterways and transportation networks but also marked the emergence of Ulysses S. Grant as a formidable military leader.

The fall of this Confederate stronghold brought significant strategic advantages to the Union cause while dealing a devastating blow to Confederate operations in the Western Theater. This battle's outcome demonstrated the effectiveness of combined arms operations and set the stage for future Union successes throughout the war.

The capture of Fort Donelson ultimately proved that the Union's military strategy was shifting toward a more aggressive and coordinated approach that would eventually lead to victory in the Civil War.