Period 5: 1844–1877

What this unit covers

The topics below follow the published US History course framework for Unit 5. This unit is worth 10–17% of the exam, so budget your time against that rather than against how long the unit takes to teach.

Lessons in this unit

• Manifest Destiny & the Sectional Crisis14 min · 3 objectivesExplain how Manifest Destiny drove territorial expansion in the 1840s · Analyze how new territories reignited the conflict over slavery · Trace the failure of political compromises to resolve sectional tensions
• The Civil War14 min · 3 objectivesIdentify the immediate causes of secession and the outbreak of war · Explain how the Emancipation Proclamation transformed the war’s purpose · Analyze the Union’s advantages and the war’s effect on the nation
• Reconstruction & Its Collapse13 min · 3 objectivesCompare presidential and congressional (Radical) Reconstruction · Explain the significance of the Reconstruction Amendments · Analyze why Reconstruction ended and what its legacy meant for Black Americans

Every term in Unit 5

All 23 terms we publish for Period 5: 1844–1877, with definitions. Reading them through is the fastest way to find the ones you cannot define — then drill those in cram mode until you can produce them without the prompt.

Popular sovereignty

Letting territorial settlers vote on slavery. Sounded democratic; turned Kansas into a battleground.

Dred Scott v. Sandford (1857)

Held that Black Americans were not citizens and that Congress could not bar slavery from territories, voiding the Missouri Compromise.

Emancipation Proclamation (1863)

Freed enslaved people in rebelling areas only, as a war measure. Redefined the war's purpose, deterred European intervention and opened Army enlistment to Black men.

Mexican-American War (1846–48)

Ended with the Mexican Cession, adding the Southwest and California — and reopening the question of slavery in the territories.

Wilmot Proviso (1846)

Proposal to bar slavery from any land taken from Mexico. Never passed the Senate, but it split parties along sectional rather than partisan lines.

Compromise of 1850

California free, a stronger Fugitive Slave Act, the slave trade ended in DC, popular sovereignty in Utah and New Mexico. Bought a decade and enraged the North.

Fugitive Slave Act (1850)

Compelled Northern citizens and officials to help capture escapees and denied the accused a jury trial. Made Northerners complicit and radicalized opinion.

Uncle Tom's Cabin (1852)

Stowe's novel dramatized slavery's cruelty for a mass Northern audience and hardened sectional feeling.

Kansas-Nebraska Act (1854)

Repealed the Missouri Compromise line in favor of popular sovereignty. Destroyed the Whigs, birthed the Republicans and produced "Bleeding Kansas".

Lincoln-Douglas debates (1858)

Senate debates over slavery in the territories; Douglas's Freeport Doctrine kept Illinois but cost him Southern support in 1860.

John Brown's raid (1859)

Failed attempt to spark a slave uprising at Harpers Ferry. Brown became a martyr in the North and proof of Northern intentions in the South.

Election of 1860

Lincoln won with under 40% of the popular vote and no Southern electoral votes, prompting secession before he took office.

Gettysburg and Vicksburg (1863)

Twin turning points: Lee's invasion was broken in the East and the Union split the Confederacy by taking the Mississippi.

Gettysburg Address

Recast the war as a test of whether a nation "conceived in liberty" could endure, tying the Union cause to the Declaration's equality clause.

Thirteenth Amendment (1865)

Abolished slavery except as punishment for crime — an exception later exploited through convict leasing.

Fourteenth Amendment (1868)

Birthright citizenship, due process and equal protection against the states. The constitutional basis of most later civil-rights litigation.

Fifteenth Amendment (1870)

Barred denying the vote on grounds of race. Its silence on literacy, property and poll taxes left the loopholes the South later used.

Freedmen's Bureau

Federal agency providing food, legal aid, labor contracts and schools to freedpeople. Founded several HBCUs; underfunded and shut down in 1872.

Black Codes

Southern laws restricting freedpeople's movement, contracts and property, recreating conditions close to slavery. Provoked Congressional Reconstruction.

Radical Reconstruction

Congress divided the South into military districts and required Black suffrage and Fourteenth Amendment ratification for readmission.

Sharecropping

Tenants farmed for a share of the crop, borrowing against it at high interest. Debt peonage kept freedpeople bound to land they did not own.

Ku Klux Klan

Paramilitary terror organization using violence to suppress Black voting and Republican organizing; targeted by the Enforcement Acts.

Compromise of 1877

Hayes took the presidency, federal troops left the South and Reconstruction ended, clearing the way for disenfranchisement and Jim Crow.

What examiners penalize here

• When evaluating Reconstruction, avoid calling it a total failure. Argue the nuance: it failed to secure immediate equality, **but** the 13th, 14th, and 15th Amendments became the legal foundation for the twentieth-century civil rights movement. That "seeds for the future" framing earns complexity points.

Practice US History

Our practice bank is drawn from across the whole course rather than filtered to one unit, which is closer to how the exam asks anyway — it will not tell you which unit a question is testing.

Questions about this unit

All 9 units of AP United States History

1. Unit 1 · Period 1: 1491–1607
2. Unit 2 · Period 2: 1607–1754
3. Unit 3 · Period 3: 1754–1800
4. Unit 4 · Period 4: 1800–1848
5. Unit 5 · Period 5: 1844–1877
6. Unit 6 · Period 6: 1865–1898
7. Unit 7 · Period 7: 1890–1945
8. Unit 8 · Period 8: 1945–1980
9. Unit 9 · Period 9: 1980–Present