American Civil War
When Lincoln's election shattered the Union and slavery's fate hung in the balance
Also known as The Civil War · War Between the States · American Civil War · The Rebellion
Hero image: "Pocket diary owned by Isaiah Goddard Hacker, a soldier in the Union Army during the American Civil War, 1864 (rbm-hacker-diary-1864~171)" by Fæ is marked with Public Domain Mark 1.0. To view the terms, visit https://creativecommons.org/publicdomain/mark/1.0/.
In short
Eleven Southern states seceded from the United States between December 1860 and June 1861, forming the Confederate States of America and triggering a four-year civil war that killed over 620,000 people. The conflict began when Confederate forces fired on Fort Sumter in Charleston Harbor on April 12, 1861, and ultimately determined whether the nation would survive as a unified country and whether slavery would be abolished.
The five-minute version
What actually happened.
The election of Abraham Lincoln in November 1860 accelerated what had been building for decades. South Carolina seceded within two months, followed by six more states that formed the Confederate States of America under Jefferson Davis. The North, led by President Lincoln, refused to recognize the breakaway nation. When Confederate President Davis ordered General P.G.T. Beauregard to take Fort Sumter—a federal garrison in Charleston harbor still flying the Union flag—the war began on April 12, 1861, with Confederate artillery opening fire at 4:30 a.m.
What followed was the deadliest conflict in American history. Neither side anticipated how long or costly it would be. The Union initially expected victory in months; the Confederacy believed European cotton dependency would force recognition and intervention. Neither calculation held. The war consumed entire generations. Ulysses S. Grant emerged from obscurity to command Union forces; Robert E. Lee became the Confederacy's finest general. Battles like Gettysburg (July 1863), with 51,000 casualties, and Sherman's March to the Sea (1864) defined industrial-scale warfare on a continent.
Lincoln's Emancipation Proclamation, issued September 22, 1862, and effective January 1, 1863, transformed the conflict from a constitutional struggle into a war for human freedom. Enslaved people fled to Union lines by the thousands, and eventually 180,000 Black soldiers fought for the North. The moral stakes clarified even as the body count mounted. Hospitals overflowed. Entire towns lost a generation of men. The nation's economy warped around military production.
By April 1865, Confederate General Lee surrendered at Appomattox, Virginia. The Union held. Slavery was abolished by the 13th Amendment. But 620,000 Americans lay dead—nearly 2% of the population. The South's infrastructure was wrecked. The Reconstruction era that followed proved nearly as traumatic as the war itself, and the racial inequities the conflict purported to settle persisted for another century. The American Civil War didn't end American history; it reset it, leaving scars that never fully healed.
Timeline
How it actually unfolded.
South Carolina secedes
South Carolina becomes the first state to secede from the Union, following Abraham Lincoln's election in November 1860.
Mississippi secedes
Mississippi becomes the second state to leave the Union.
Confederate States formed
Delegates from six seceded states meet in Montgomery, Alabama, to establish the Confederate States of America.
Jefferson Davis elected Confederate President
Jefferson Davis of Mississippi is elected president of the newly formed Confederacy.
Lincoln inaugurated
Abraham Lincoln is inaugurated as the 16th President of the United States.
Fort Sumter attacked
Confederate forces under General P.G.T. Beauregard open fire on Fort Sumter in Charleston Harbor, marking the start of armed conflict.
Lincoln calls for volunteers
President Lincoln calls for 75,000 volunteers to suppress the rebellion, prompting four more states to secede.
First Union casualty
Colonel Elmer Ellsworth is shot and killed in Alexandria, Virginia—the first notable casualty of the war.
First Battle of Bull Run
The first major battle of the war occurs near Manassas, Virginia; Confederate forces defeat Union General Irvin McDowell's army.
By the numbers
The countable parts.
Confederate states at war's start
0 states (South Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana, Texas)
Confederate states by war's end
0 states (added Virginia, Arkansas, Tennessee, North Carolina)
War duration
0 years, 4 months (April 1861 – April 1865)
The world it landed in
What was on the radio, the screen, and everyone's mind.
Battle Hymn of the Republic — Julia Ward Howe (lyrics), William Steffe (melody)
Published in The Atlantic Monthly in November 1861; became the unofficial anthem of the Union cause.
Dixie — Daniel Decatur Emmett
Originally a minstrel song, it became the de facto anthem of the Confederacy despite its Northern composition.
Same week, elsewhere
The Civil War era produced vast amounts of soldier letters, battlefield photography (especially Alexander Gardner and Mathew Brady), and newspaper reporting that defined modern war documentation. Lincoln's rhetoric—the Gettysburg Address (November 1863), Second Inaugural Address (March 1865)—set the standard for presidential moral language. Popular culture was dominated by military enlistment drives, patriotic songs, and increasingly realistic depictions of combat's human cost.
Then & now
The world the event landed in vs. the one it left behind.
U.S. Population
31.4 million
1861
335 million
2023
The nation more than tenfold larger; the war's death toll of 620,000+ represented roughly 2% of the population at the time.
Enslaved Persons in U.S.
3.95 million
1860
0
2024
Slavery is constitutionally prohibited; however, mass incarceration and labor disparities persist.
Cost of War (nominal dollars)
$5.2 billion
1865
$130+ billion (adjusted for inflation)
2024
The war consumed roughly 27% of Northern GDP annually at its peak; no subsequent U.S. conflict has approached that fiscal burden.
Impact
What followed.
The American Civil War (1861–1865) killed more than 620,000 soldiers and fundamentally rewrote the nation's constitutional order, abolishing slavery through the 13th Amendment and forcing a violent reckoning over federalism that no political compromise could prevent. It ended the question of whether the United States would endure as a single republic or fragment into competing sovereignties.
Threads pulled by this event
- 1863
Emancipation Proclamation
Abraham Lincoln issued the executive order on January 1, 1863, declaring enslaved people in Confederate states to be free, transforming the war from a fight for union into a fight for liberation.
- 1865
13th Amendment Ratification
Congress passed and states ratified the 13th Amendment in December 1865, permanently abolishing slavery throughout the United States and its territories.
- 1867
Reconstruction Acts
Congress imposed military rule on the South and required Southern states to ratify the 14th Amendment (guaranteeing equal protection) and 15th Amendment (protecting voting rights regardless of race) to rejoin the Union.
- 1868
Rise of the Republican Party
The Republican Party, founded in 1854, solidified as the dominant Northern party by 1868 under Ulysses S. Grant, reshaping the two-party system for the next generation.
- 1877
Jim Crow Era Begins
The Compromise of 1877 ended Reconstruction and Northern occupation of the South, allowing Southern states to implement discriminatory Black Codes and segregation laws that would persist for nearly a century.
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