Mexican War and Wilmot Proviso (1846) increase sectional conflict

Gold rush makes California eligible for statehood — free or slave?

U.S. confronts Mexico and Britain: annexes Texas (1845), acquires Oregon (1846), fights Mexican War (1846–1848) extending U.S. borders to Pacific

Ideology of Manifest Destiny prompts U.S. expansionism

Free-Soil Party (1848) advocates white smallholder farm society

Women seek legal rights at Seneca Falls (1848)

Irish immigrants build northern canal system

Some states default on canal bonds

Walker Tariff (1846) lowers rates, increases foreign imports

Whites migrate to Oregon and California

Arrival of millions of Germans and Irish causes social conflicts

Wars against Seminole peoples in Florida (1835–1842, 1855–1858)

Compromise of 1850

Whig Party disintegrates; Know-Nothing Party attacks immigrants

Kansas-Nebraska Act (1854) sparks creation of Republican Party

President Pierce opens Japan to trade; seeks to expand American territory and slavery into Caribbean by diplomacy and filibustering actions

Harriet Beecher Stowe’s Uncle Tom’s Cabin (1852) attacks slavery

Dred Scott decision (1857) opens way to legalize slavery nationwide

Southern secessionists agitate for independence

Enslaved blacks expand cotton output in South

White settlers expand farm society to trans-Mississippi west

Entrepreneurs promote railroad building and manufacturing in North and Midwest

Conflict of Hispanics and Anglos in the Southwest

White diseases and brutality kill most California Indians

Comanches and Sioux dominate Great Plains peoples and control trade in horses and buffalo hides

Eleven southern states secede from Union, sparking Civil War (1861–1865); the Union’s triumph preserves a continental nation

Fourteenth Amendment (1868) extends legal and political rights

U.S. diplomacy and Union army victories in 1863 cause British government to stop sale of ironclad ships to the Confederacy

Secretary of State Seward buys Alaska from Russia (1867)

Burlingame Treaty (1868) protects missionaries in China and limits Chinese immigration

Confederate States of America (1861–1865) vow to continue slavery

Republicans seek to impose equal rights ideology on South

Black families accept ideal of domesticity

Republicans enact Whigs’ economic policies: Homestead Act (1862), railroad aid, high tariffs, and national banking

Women assume new tasks in war economies

Emancipation Proclamation (1863) and Thirteenth Amendment (1865) free blacks from slavery

Aided by Freedmen’s Bureau, African Americans struggle for freedom, land, and education

Fifteenth Amendment (1870) extends vote to black men

Compromise of 1877 ends Reconstruction

Britain pays the U.S. $15.5 million for the depredations of the Alabama during the war

Anti-Chinese riots in San Francisco in late 1870s prompt Chinese Exclusion Act (1882)

Ku Klux Klan attacks Reconstruction governments

Republicans embrace classical liberalism

White elites challenge ideal of universal suffrage and deny women’s suffrage

Sharecropping spreads in South

Ranchers create cattle empire on Great Plains

Depression of 1873 halts railway expansion

U.S. wars against Plains Indians (Cheyennes, Sioux, Apaches, and Nez Perce) open their lands to white miners, ranchers, and farmers

Dawes Act (1887) seeks Indian assimilation