​Where the U.S. Began

​The United States began as 13 British colonies located along the Atlantic Coast. After the Treaty of Paris (1783) ended the American Revolution, the new nation gained land east of the Mississippi River. This land became the foundation for westward expansion. As the population grew, Americans looked west for land ownership, economic opportunity, and natural resources. These goals shaped future decisions about territory and settlement.

Circle the reason Americans wanted more land on your paper

​The Louisiana Purchase (1803)

​In 1803, the United States purchased a large territory from France called the Louisiana Purchase. This agreement doubled the size of the nation and gave the U.S. control of the Mississippi River, which helped trade and transportation. The purchase supported Manifest Destiny by allowing Americans to expand westward and create new settlements. It also increased debates over slavery in new territories.

​Florida & the Adams-Onís Treaty

​The Adams-Onís Treaty (1819) transferred Florida from Spain to the United States. In return, the U.S. gave up claims to Spanish land in the Southwest. This treaty reduced border disputes and strengthened U.S. control in the Southeast. Expansion through treaties showed how the government used negotiation instead of war to gain territory.

​Underline the reason the treaty was important on your paper

​Oregon, Texas, and Manifest Destiny

​Americans moved west into the Oregon Territory, believing expansion was their right. The U.S. later annexed Texas, which increased tension with Mexico. These actions were driven by Manifest Destiny, population growth, and the desire for farmland. However, expansion also increased conflicts over slavery and land ownership.

​The U.S.–Mexican War

​The U.S.–Mexican War (1846–1848) began after disagreements over Texas borders. The war ended with the Treaty of Guadalupe Hidalgo, where Mexico ceded a large amount of land to the U.S., including present-day California and the Southwest. This land became known as the Mexican Cession and expanded the U.S. to the Pacific Ocean.

​Gadsden Purchase & Transportation

​In 1853, the U.S. completed the Gadsden Purchase, gaining land from Mexico to build a railroad route. Later, the Transcontinental Railroad connected the East and West, increasing trade, settlement, and economic growth. Transportation improvements made westward expansion faster and more profitable.

​Conflict Over Slavery in New Territories

​As the nation expanded, Americans argued over whether new states would allow slavery. The Missouri Compromise, Compromise of 1850, and Kansas-Nebraska Act attempted to reduce conflict by balancing free states and slave states or allowing popular sovereignty. These compromises showed how westward expansion increased sectional tension.

​The Missouri Compromise

​As the United States expanded westward, leaders worried about the balance between free states and slave states. The Missouri Compromise of 1820 was created to reduce conflict. Missouri wanted to enter the Union as a slave state, which would upset the balance in Congress. To solve this problem, Missouri entered as a slave state and Maine entered as a free state.

The compromise also created a geographic boundary at 36°30′ latitude. Slavery was banned north of this line (except Missouri) and allowed south of it. This law showed how westward expansion increased tension over slavery and forced Congress to create compromises to preserve the Union.

Although the Missouri Compromise temporarily reduced conflict, it did not solve the issue of slavery. Instead, it showed that expansion made disagreements more serious over time.

​The Compromise of 1850

​After the Mexican Cession, the nation again argued over slavery in new territories. The Compromise of 1850 attempted to settle these disagreements. California entered the Union as a free state, which upset the balance between free and slave states. To gain Southern support, Congress passed a stronger Fugitive Slave Act, requiring escaped enslaved people to be returned.

The compromise also allowed popular sovereignty in Utah and New Mexico, meaning settlers could vote on slavery. This reflected the belief that people should decide their own laws. However, the Fugitive Slave Act angered many Northerners and increased resistance to slavery.

The Compromise of 1850 showed that westward expansion created political, social, and moral conflicts that were becoming harder to solve peacefully.

​The Kansas–Nebraska Act (1854)

​The Kansas–Nebraska Act allowed settlers in Kansas and Nebraska to vote on whether to allow slavery using popular sovereignty. This law repealed the Missouri Compromise by allowing slavery north of the 36°30′ line. As a result, pro-slavery and anti-slavery settlers rushed into Kansas.

This led to violent conflict known as Bleeding Kansas, where groups fought over control of the territory. Instead of reducing tension, the Kansas–Nebraska Act increased sectional violence and mistrust. It also weakened faith in compromise as a solution to slavery.

The act showed that westward expansion no longer just created political debates—it caused physical violence and pushed the nation closer to civil war.

​The Gold Rush

​The California Gold Rush (1848) brought thousands of settlers west in search of gold. This caused rapid population growth, economic opportunity, and environmental change. It also increased conflict with American Indian groups and sped up California’s admission as a state.