The American Civil War, fought from 1861–1865 between the Union and 11 Southern states that had seceded to form the Confederacy, remains the nation's deadliest conflict, with an estimated 700,000 soldiers killed—more than in all other US wars combined. About two-thirds of those deaths resulted from disease rather than combat.
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Confederate leaders cited slavery as the reason for secession. Vice President Alexander Stephens called it the Confederacy's "cornerstone," built on "the great truth that the negro is not equal to the white man."
During the Atlantic Slave Trade (1526–1867), about 12.5 million Africans were forced onto ships; only 10.7 million survived to reach the Americas. Fewer than 400,000 arrived in what became the United States—the rest were taken to the Caribbean or Latin America.
The American Battlefield Trust's animated maps trace every major Civil War battle with moving troop lines, narration, and historical context—bringing the strategies, turning points, and human cost of the war to life.
The addition of new western lands forced the nation to confront whether slavery would spread beyond the South. Each debate over the admission of a new state sharpened the divide between free and slaveholding regions
Abraham Lincoln's election on an anti-slavery expansion platform convinced many Southerners that their way of life was under threat. Within three months, seven states seceded from the Union—forming the Confederacy before Lincoln took office in March 1861.
Lincoln's 1860 victory came entirely from Northern and Western states, as his name was excluded from most Southern ballots. The outcome highlighted the deep divisions and regional polarization in the country.
Confederate forces fired on Union-held Fort Sumter in Charleston Harbor on April 12, 1861, after Lincoln refused to surrender it. The bombardment lasted 34 hours, forcing a Union surrender and marking the beginning of the Civil War.
Between December 1860 and June 1861, eleven Southern states officially seceded to form the Confederacy. Pro-Confederate factions in Missouri and Kentucky also declared secession, but both states remained largely under Union control throughout the war.
Delivered on November 19, 1863, at the dedication of a national cemetery, Lincoln's 272-word Gettysburg Address reframed the war as a struggle for equality. The speech would be cited as a moral touchstone for later movements such as women's suffrage and civil rights.
In February 1861, detective Allan Pinkerton uncovered a plot to kill Abraham Lincoln en route to his inauguration. Lincoln secretly altered his travel plans and snuck into Washington DC to take the oath of office. Pinkerton later founded the well-known Pinkerton National Detective Agency.
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