Heimler’s History: Lecture on AP U.S. History Unit 5 (1844-1877)

Westward Expansion & Manifest Destiny

Key Time Period: 1844-1877
Concept: Manifest Destiny
- Definition: The belief that Americans were destined by God (Providence) to expand across the continent from the Atlantic to the Pacific.
- Coined by: John O’Sullivan in July 1845.
- Implications: Justified U.S. territorial expansion.

Access to Resources
- Discovery of gold in California (1848) -> California Gold Rush.
- Subsequent gold and silver discoveries in Colorado, the Dakotas, and Nevada.
Economic and Homesteading Opportunities
- Preemption Acts of the 1830s and 1840s made land cheap for settlers.
- Predominantly middle-class migration due to travel costs.
Religious Refuge
- Mormons fled the Midwest due to persecution (e.g., polygamy) and settled in Utah.
- Continued migration to Utah over 20 years (~70,000 people).

James K. Polk’s Election (1844)
- Big proponent of Manifest Destiny.
- Aimed to annex Texas and Oregon.

Early Settlements: 1820s, Americans settled in Texas (part of Mexico).
- Mainly Southern, Protestant, slave-owning.
Mexican Requirements (1829): Convert to Catholicism & outlaw slavery.
American Reaction: Ignored laws, continued immigration.
Texas Independence (1836):
- Led by Sam Houston, revolted against Mexico.
- Key Events:
  - Battle of the Alamo (Mexican victory).
  - Battle of San Jacinto (Texans capture Mexican general, forced treaty).
- Mexican government did not recognize independence.
- U.S. Annexation rejected by Jackson and Van Buren due to war concerns.

Claims: Both British and Americans.
- British: Established fur trade.
- Americans: Missionaries and farmers settled there.
Resolution:
- Polk negotiated settlement -> Oregon Territory divided at 49th parallel.

Annexation of Texas: Led to tensions with Mexico, setting stage for war (to be discussed in the next lecture).
Study Strategy: Consider subscribing to Heimler’s History for AP U.S. History study aids.