According to Confederate leaders, the defense of slavery was the primary reason for secession.

Abraham Lincoln's election in 1860 triggered a cascade of Southern secessions and the formation of the Confederacy, culminating in the Confederate attack on Fort Sumter in Charleston, South Carolina.

Abraham Lincoln's victory in 1860 sparked Southern secession—even before his inauguration

Abraham Lincoln's election on an antislavery 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.

Was the Civil War really about states' rights?

The Civil War was fought over slavery, and Confederate leaders and supporters admitted as much in the build-up to the war and after. But later on, after the South's defeat, the lie of the Lost Cause was pushed—and it persists to this day. This four-minute video details the story of the Lost Cause, "state's rights", Confederate monuments, and the machinations behind them.

11 states formed the Confederacy, with 2 others claiming allegiance

Between December 1860 and June 1861, 11 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.

US westward expansion—and the status of slavery in the new territories—was a major cause of the American Civil War

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.

The Emancipation Proclamation shifted the purpose of the war for the Union

Issued on Jan. 1, 1863, the Emancipation Proclamation declared enslaved people in Confederate-held territory free, redefining the Union's cause from merely preserving the nation to abolishing slavery.

A section condemning slavery, originally written by Thomas Jefferson, was cut from the Declaration of Independence.

Hear how the world reacted to the American Civil War

European nations closely watched the Civil War for its economic and political consequences. Some European nations quietly engaged diplomatically with the Confederacy but withheld recognition. When the Union made slavery's abolition a central cause, European public opinion turned sharply against the South.

View animated battle maps from every major skirmish of the American Civil War.

A section condemning slavery was cut from the Declaration

Thomas Jefferson included a passage in his original draft denouncing slavery. This explainer from the Henry Ford Museum explores why Congress removed it to preserve colonial unity and how that decision shaped the nation's earliest political compromises.

The South built its wealth largely from slave labor

Before the Civil War, the Southern economy relied on roughly 4 million enslaved people producing cash crops such as cotton, rice, and sugarcane. Their forced labor generated immense profits—the South produced 75% of the world's cotton by 1860.

Support for slavery helped drive Texas to revolt against Mexico

Mexico abolished slavery in 1829, but many Anglo-American settlers in Texas brought enslaved people and refused to comply. Their desire to preserve slavery was a major factor in Texas’s 1836 rebellion and independence from Mexico.

Despite the Juneteenth announcement that they were free, some enslaved people were still held captive.

The Lincoln-Douglas debates sharpened the national divide over slavery

In 1858, Abraham Lincoln and Senator Stephen Douglas debated while competing for an Illinois Senate seat. Their seven debates, reprinted nationwide, brought the question of slavery to the forefront—further polarizing the country and propelling Lincoln to national prominence.

The Dred Scott decision denied citizenship to people of African descent

In 1857, the Supreme Court ruled in Dred Scott v. Sandford that Black Americans could not be US citizens. The decision heightened an already brewing conflict and became a key factor in pushing the nation toward civil war.

Most Confederate soldiers and leaders after the Civil War were pardoned

After surrender, most Confederate soldiers were pardoned and returned home, while leaders like Jefferson Davis faced short imprisonment. The South came under military occupation, Confederate money became worthless, and many former officers were barred from public office.

Lincoln's original reconstruction vision prioritized reconciliation

Proposed in 1863, Lincoln's Ten Percent Plan offered lenient readmission for Southern states once 10% of voters pledged loyalty and ended slavery. It was adopted in a few Union-occupied areas but was only partially implemented before his assassination in 1865.

The Confederate flag that most people recognize was not the national flag

The familiar Confederate flag was actually a battlefield banner; the Confederacy's true national flag, the "Stars and Bars," featured a blue canton with white stars and red-white-red stripes resembling the US flag.

The abolitionist movement long predated the Civil War

Beginning in the late 18th century, abolitionists like Frederick Douglass, William Lloyd Garrison, and Sojourner Truth campaigned through newspapers, lectures, and political action to end slavery.

The Kansas-Nebraska Act sparked violence that foreshadowed the Civil War

The 1854 Kansas-Nebraska Act let settlers vote on whether to allow slavery, repealing the Missouri Compromise. Competing proslavery and antislavery groups poured into Kansas, sparking years of bloody conflict known as "Bleeding Kansas."

Abolitionists shaped American history from the Revolution to the Civil War

Abolitionists of all backgrounds organized against slavery from the founding era onward. Historian Manisha Sinha argues that their decades of activism fundamentally shaped American democracy and made emancipation possible.

The Civil War turned the Continental Divide into an American symbol of identity

Historians argue that the boundary only became a celebrated American symbol in the 1860s, when Civil War-era leaders promoted a west-east geographic divide to replace the devastating north-south political divide, and that the term's use spiked after the transcontinental railroad crossed it in 1868.

The Civil War permanently strengthened federal power

The Civil War expanded federal power through emancipation, national military mobilization, and postwar civil rights laws, permanently strengthening the national government and shifting the balance of authority away from the states.

Congress's Wade-Davis Bill demanded harsher terms for Southern reentry

Passed in 1864, the Wade-Davis Bill required 50% of white male voters to swear loyalty and guarantee emancipation before readmission. Lincoln pocket-vetoed it, rejecting Congress's stricter approach.

The nullification crisis tested whether states could defy federal law

In the 1830s, South Carolina declared federal tariffs void within its borders. President Andrew Jackson threatened military force, Congress passed a compromise tariff, and the episode ended with federal authority prevailing over state nullification.

Madison condemned slavery in theory while owning slaves

James Madison argued that slavery violated Revolutionary ideals. Yet, he inherited and managed more than 100 enslaved people to operate the family's 3,000-acre plantation, brought enslaved laborers to the White House, and later sold them for personal profit.

Congress descended into fistfights, duels, and violence before the Civil War

In the decades before the Civil War, members of the United States Congress carried weapons, assaulted colleagues, and, in one case, a congressman killed another in a duel. The violence was driven largely by sectional conflict over slavery and foreshadowed the nation's descent into war.

Abraham Lincoln received only 40% of the popular vote in the 1860 election, highlighting the deep divisions in the country on the eve of the Civil War.

The Royal Governor of Virginia offered slaves their freedom if they escaped and fought for the British in the American Revolutionary War.

The end of Reconstruction paved the way for Jim Crow segregation

After federal troops withdrew in 1877, white Democrats regained control of Southern governments, dismantled Reconstruction reforms, and imposed segregation laws. By the 1890s, Jim Crow statutes had entrenched racial discrimination and Black disenfranchisement across the South.

Southern race riots in 1866 galvanized support for more radical Reconstruction

In 1866, white mobs in Memphis and New Orleans killed dozens of Black residents and burned Black neighborhoods. The massacres horrified Northerners, convincing Congress that stronger federal action was needed to protect freedpeople's rights and enforce Reconstruction.

Later in life, Washington privately grew critical of slavery—while continuing to uphold it publicly

His private letters increasingly described slavery as unjust and incompatible with Republican ideals, and his final will ordered the eventual emancipation of those he legally owned. At the same time, he enforced slave labor, signed pro-slavery laws, and took no public action to dismantle the system.

Read an annotated 1866 essay by abolitionist Frederick Douglass, where he laid out his vision for reshaping America after the Civil War.

White supremacist groups like the Ku Klux Klan emerged to undermine Reconstruction

Founded in 1865 by former Confederate officers in Tennessee, the Ku Klux Klan used terror, murder, and intimidation to suppress Black political power and restore white Democratic control across the postwar South.

Some historians claim that Mexico's victory at Puebla may have prevented France from arming the Confederacy

According to some experts, Napoleon III planned to ship weapons from Mexico to Confederate forces to break the Union naval blockade. The delay caused by the Battle of Puebla meant French resources didn't reach the Texas border until after the Union Army's decisive victory at Vicksburg.

Adams was a vocal opponent of slavery during the Revolutionary era

In letters written during the Revolution, Adams clearly opposed slavery—calling it an unjust scheme and highlighting the contradiction of fighting for freedom while enslaving others. Read it in her own words here in a letter to John Adams.

Francis Scott Key was opposed to slavery in principle, though he held slaves and was opposed to abolition.

In the midst of the Civil War, Lincoln rapidly expanded presidential power

Abraham Lincoln suspended habeas corpus, expanded the army without congressional approval, and issued the Emancipation Proclamation—despite likely lacking authority to unilaterally alter national slave law. His actions set precedents for expanded presidential power in wartime.

Learn how Mexico’s anti-slavery stance shaped the US–Texas conflict

Historian Alice Baumgartner explores how Mexico’s abolition of slavery clashed with Anglo settlers' ambitions in Texas. The episode reveals how enslaved people fled south to freedom, reshaping the politics that led to Texas independence and the Mexican-American War.

See the army generals who helped define the Civil War

Hear profiles of the Union and Confederate commanders whose choices defined the war's outcome—from Grant and Lee to Sherman, Jackson, and others. See how their actions, tactics, and skills shaped the Civil War.

The Prize Cases established that the president can respond to an attack without waiting for Congress to act

When Lincoln blockaded Confederate ports at the start of the Civil War without congressional authorization, the Supreme Court upheld his actions, ruling that a president does not initiate war by responding to an attack and need not wait for Congress when the nation is already under threat.

Southern Black Codes sought to preserve prewar racial labor structures

With little federal oversight, Southern states enacted laws effectively reestablishing slavery's economic and social order. These laws, known as the "Black Codes," restricted freed people's movement, labor, and property rights.

Mississippi didn't officially ratify the Thirteenth Amendment banning slavery until 2013, nearly 150 years after it passed.

Where was the Civil War fought?

The Civil War is commonly described as a war between northern and southern US states, but where was the war actually fought? Watch this interactive map and timeline to see who fought who and when. Click on specific battles to learn more about each fight.

Robert Smalls escaped slavery by piloting a stolen Confederate ship to freedom, then became an influential Black political leader during Reconstruction.

The South was placed under federal military rule during Reconstruction

Beginning in 1867, the Reconstruction Acts divided 10 former Confederate states into five military districts, each governed by a Union general. Federal troops supervised elections, enforced civil rights, and maintained order under direct congressional authority.

The 13th Amendment's criminal exception enabled new forms of forced labor

Southern states exploited the amendment's clause allowing slavery "as punishment for crime" to arrest thousands of Black Americans on minor charges, leasing them to private employers through convict labor systems that persisted for decades.

The Missouri Compromise temporarily eased tensions over slavery's expansion

Passed in 1820, the Missouri Compromise admitted Missouri as a slave state and Maine as a free state—maintaining the fragile balance between proslavery and antislavery states in Congress. It also banned slavery north of latitude 36°30′.

See how the Declaration evolved from draft to final text

John Adams urged Congress to choose Thomas Jefferson to draft the Declaration because of his literary skill and low-profile reputation. Read Jefferson's initial draft, which included passages later removed, including a forceful denunciation of slavery.

The final shots of the Civil War were fired in the Arctic over 2 months after the South's surrender.