US Westward Expansion & Civil War Era Key Concepts

Bear Flag

Revolt in California (1846) where American settlers declared independence from Mexico — created the short-lived California Republic (Bear Flag Republic).

Compromise of 1850

A deal to keep balance between free and slave states: California = free state, Stronger Fugitive Slave Law, Popular sovereignty in new territories (Utah & New Mexico), Slave trade banned in D.C.

Dred Scott

Enslaved man who sued for freedom → Supreme Court said he wasn't a citizen and Congress couldn't ban slavery anywhere — big win for the South.

Free Soil

Movement/party that wanted no slavery in new western territories — slogan: 'Free Soil, Free Speech, Free Labor, Free Men.'

Fugitive Slave Laws / Personal Liberty Laws

Fugitive Slave Laws: Required escaped slaves to be returned to owners, even in free states. Personal Liberty Laws: Northern states' response — tried to protect escaped slaves from being sent back.

Guadalupe-Hidalgo

1848 treaty that ended the Mexican-American War — U.S. got land (California, Southwest) and set the Rio Grande as the border.

James Polk

U.S. president (1845-1849), big on Manifest Destiny — got Oregon, California, and led U.S. into Mexican War.

John Brown

Abolitionist who used violence against slavery — led raids in Kansas ('Bleeding Kansas') and at Harpers Ferry.

Kansas-Nebraska Act

(1854) Let people in Kansas & Nebraska vote on slavery (popular sovereignty) → led to 'Bleeding Kansas'.

Lecompton

Pro-slavery constitution proposed in Kansas — caused huge controversy and rejected by anti-slavery settlers.

Lincoln-Douglas

Series of debates (1858) between Abraham Lincoln and Stephen Douglas over slavery's expansion — made Lincoln famous.

Manifest Destiny

Belief that Americans were destined by God to expand westward across the continent.

Missouri Compromise

(1820) Missouri = slave state, Maine = free state; slavery banned north of 36°30' line in Louisiana Territory.

Popular Sovereignty

Idea that people in a territory should vote to decide if slavery is allowed.

Republican Party

Founded in 1850s to oppose spread of slavery — Abraham Lincoln's party.

Rio Grande

River that became the border between Texas and Mexico after the Mexican-American War.

Sam Houston

Leader of the Texas Revolution, won independence at San Jacinto, and became first president of Texas.

San Jacinto

Battle where Texans defeated Mexico (1836) and won Texas independence — 'Remember the Alamo!'

Slidell

John Slidell — U.S. diplomat sent to Mexico to buy California before war; Mexico refused to meet him, leading to war.

Underground Railroad

Secret routes and safe houses that helped enslaved people escape to freedom in the North or Canada.

War with Mexico

(1846-1848) U.S. vs. Mexico; U.S. won and gained huge lands in the Southwest through Treaty of Guadalupe-Hidalgo.

Wilmot Proviso

Proposed law to ban slavery in any land won from Mexico — never passed but deepened North/South tensions.

Young America

Movement promoting U.S. expansion (especially in Latin America) and spreading democracy — tied to Manifest Destiny ideas.