- After Fort Sumter was attacked (April 12, 1861), President Abraham Lincoln issued a call for 75,000 volunteers, and Grant rejoined the army on April 23.
- Grant was appointed Colonel of the 21st Illinois Regiment of Volunteers on June 17.
- Established headquarters in Cairo, Illinois, in command of the district of southern Illinois and southeastern Missouri (September 4).
- Occupied Paducah, Kentucky, giving the Union a strong foothold in the West without bloodshed (September 6).
- In his first Civil War battle, Grant defeated a Confederate force at Belmont, Missouri, and then withdrew (November 7).
- February 6, 1862: captured Fort Henry on the Tennessee River.
Fort Donelson (February 12 – 16):
- Along with Fort Henry, first major Union victory of the war.
- Grant wrote to Confederate General Simon Bolivar Buckner on February 16, 1862, “No terms except an unconditional and immediate surrender can be accepted. I propose to move immediately upon your works.” This earned him the nickname “Unconditional Surrender” Grant.
- Surrender of about 13,000 Confederates marked the largest capture of men in the history of the Western Hemisphere up to that time.
- Named (two-star) Major General of Volunteers.
Shiloh (April 6 – 7):
- Grant faced General Albert Sidney Johnston, widely considered at the time the finest soldier in the Confederate army; Johnston was killed during the battle and replaced by P.G.T. Beauregard.
- After initially being attacked and driven back, Grant won a staggering (but bloody) victory, demonstrating that the war would last much longer than many initially predicted.
After victories at Iuka (September 19) and Corinth (October 4) in Mississippi, Grant was named commander of the Department of the Tennessee (October 25).
The Vicksburg Campaign (November 2, 1862 – July 4, 1863):
- One of the most brilliant displays of generalship in history.
- Vicksburg was considered a virtually impenetrable fortress and was the largest obstacle to Union control of the Mississippi, a critical aim of the war.
- After the seemingly dormant Campaign of the Bayous, Grant made a daring move across the Mississippi River with inferior numbers (1863).
- Won five battles in 17 days: Port Gibson (May 1), Raymond (May 12), capture of Jackson (May 14), Champion’s Hill (May 16), and Big Black River Bridge (May 17).
- Two unsuccessful assaults on Vicksburg (May 19 and May 22).
- Siege of Vicksburg (May 19 – July 4).
- July 4, 1863: Surrender of Vicksburg to Grant by Confederate General John C. Pemberton. Largest capture of men and arms in history up to that point: 30,000 troops (including 15 generals) and 172 cannon surrendered.
- The Confederacy was now virtually divided in half, and the South had suffered perhaps its worst strategic blow in the entire war.
Named commander of the Military Division of the Mississippi, which placed him in command of the Western theater of the war (October 16).
- Victory at Orchard Knob (November 23).
- Victory at Lookout Mountain (November 24).
- Victory at Missionary Ridge (November 25), a position held by the Confederates and thought to be impregnable, but taken by Grant’s troops in one of the most remarkable tactical victories of the war.
- These victories gave the Union control of Chattanooga, a major east-west railroad junction, and marked the successful completion of Grant’s western campaigns.