Westward Expansion describes how the United States grew across North America during the 1800s through purchases, treaties, migration, and war. Manifest Destiny was the belief that the nation was meant to expand from the Atlantic Ocean to the Pacific Ocean. Students need this cheat sheet to connect key dates, causes, effects, and groups affected by expansion.
It also helps organize a complicated topic into clear patterns for review.
Key Facts
- The Louisiana Purchase in 1803 doubled the size of the United States and gave the country control of land west of the Mississippi River.
- Manifest Destiny was the belief that U.S. expansion across the continent was justified, but it often ignored the rights of Native peoples and Mexico.
- The Oregon Trail was a major migration route that carried thousands of settlers west to Oregon Country during the 1840s and 1850s.
- The Texas Revolution led to the Republic of Texas in 1836, and Texas became a U.S. state in 1845.
- The Mexican-American War lasted from 1846 to 1848 and ended with the Treaty of Guadalupe Hidalgo.
- The Treaty of Guadalupe Hidalgo in 1848 gave the United States land that became parts of California, Nevada, Utah, Arizona, New Mexico, Colorado, and Wyoming.
- The California Gold Rush began in 1849 and caused rapid migration, population growth, and major changes for Native communities and the environment.
- Westward Expansion increased U.S. land and economic opportunity, but it also caused displacement, broken treaties, conflict, and loss of land for Native American nations.
Vocabulary
- Manifest Destiny
- The belief that the United States was destined to expand across North America from the Atlantic Ocean to the Pacific Ocean.
- Louisiana Purchase
- The 1803 land purchase from France that doubled the size of the United States.
- Annexation
- The act of adding a territory or region to an existing country.
- Treaty of Guadalupe Hidalgo
- The 1848 treaty that ended the Mexican-American War and transferred a large amount of land from Mexico to the United States.
- Oregon Trail
- A long overland route used by settlers traveling west to Oregon Country in the 1800s.
- Displacement
- The forced movement of people from their homeland, often caused by war, settlement, or government policy.
Common Mistakes to Avoid
- Saying Manifest Destiny was only about geography is wrong because it was also an idea used to justify political power, settlement, and expansion.
- Confusing the Louisiana Purchase with the Mexican Cession is wrong because the Louisiana Purchase was bought from France in 1803, while the Mexican Cession came after war with Mexico in 1848.
- Describing westward movement as peaceful is wrong because expansion involved conflicts, broken treaties, forced removals, and violence against Native American nations.
- Forgetting the role of push and pull factors is wrong because settlers moved west for reasons such as cheap land, gold, trade, religion, and escaping economic hardship.
- Assuming all Americans supported expansion is wrong because some people opposed it due to concerns about slavery, war, Native rights, or the power of the federal government.
Practice Questions
- 1 How many years passed between the Louisiana Purchase in 1803 and the Treaty of Guadalupe Hidalgo in 1848?
- 2 Texas became a U.S. state in 1845, and the Mexican-American War began in 1846. How many years later did the war begin?
- 3 List two pull factors that encouraged settlers to move west and one effect of that migration.
- 4 Explain why Westward Expansion can be seen as both an opportunity for some groups and a source of harm for others.