Westward Expansion: Manifest Destiny and American Growth

Published on October 4, 2025

Westward Expansion (1800s-1890s) was a period of rapid territorial growth for the United States, driven by the belief in Manifest Destiny - the idea that America was destined to expand across the continent.

Manifest Destiny

Coined by journalist John O'Sullivan in 1845, Manifest Destiny justified expansion as a divine right. It fueled policies that doubled the size of the United States and shaped national identity.

Key Acquisitions

Several major land purchases and treaties expanded US territory:

• Louisiana Purchase (1803): Doubled the size of the US for $15 million from France.
• Florida (1819): Acquired from Spain through the Adams-Onís Treaty.
• Texas Annexation (1845): Following Texas independence from Mexico.
• Oregon Territory (1846): Shared with Britain, settled by compromise.
• Mexican-American War (1846-1848): Resulted in California and Southwest territories.
• Alaska Purchase (1867): Bought from Russia for $7.2 million.

Trails and Migration

Pioneers traveled west using famous routes:

• Oregon Trail: 2,000-mile route to Oregon Territory.
• California Trail: Led to the Gold Rush of 1849.
• Santa Fe Trail: Connected Missouri to New Mexico.
• Mormon Trail: Used by Latter-day Saints seeking religious freedom.

Impact on Native Americans

Expansion displaced indigenous peoples:

• Trail of Tears (1838-1839): Forced relocation of Cherokee and other tribes.
• Sand Creek Massacre (1864) and other conflicts.
• Reservation system established, confining tribes to specific areas.

Economic and Social Changes

Westward movement spurred economic growth through farming, mining, and railroads. It also intensified debates over slavery, leading to the Civil War. The frontier experience shaped American culture and individualism.

Westward Expansion transformed the United States from a coastal nation into a continental power, but at great human cost to Native Americans and through the expansion of slavery.