Pioneers and the Frontier

Expansionists seek Manifest Destiny


  • John O’Sullivan – was a journalist who wrote an influential editorial in the New York Morning News in December 1845 in favor or expansion into the west.  He used the phrase manifest destiny which became popular.
      • O’Sullivan stated in the editorial: “The American claim is by the right of our manifest destiny to overspread and possess the whole of the continent which Providence has given us for the development of the great experiment of liberty and … self government entrusted to us.”


  • Manifest Destiny refers to the belief that God wanted the US to own all of North America.  The phrase was later used in the early 20th century during the imperialism debates that raged concerning US expansion beyond continental North America.


  • Southern expansionists objective was to add more slave states in order to strengthen their political position in Congress.


Americans traded with Mexico

  • Santa Fe Trail- was the route many from Missouri used to open trade across the Great Plains.  The route ended in Santa Fe, the capital of New Mexico.  The Mexican officials welcomed trade with the Americans and commerce continued to flourish along the route.
      • The American traders offered manufactured goods
      • The New Mexicans offered horses, mules, furs, and silver

Mountain Men Cross the Rockies

  • Mountain Men- were traders who went up the Missouri River and into the Rocky Mountains seeking valuable furs and beaver in the mountain streams.  Most of them worked for two large fur companies which provided their supplies.


  • Jedediah Smith- was a mountain man who crossed the Great Basin and the Sierra Nevada Mountains to reach California.  In addition to trapping, he traded with Mexican residents.
    • California Trail – Jedediah Smith’s trade and migration route that linked the US to the Pacific Coast



Missionaries Reached Oregon

  • Oregon Trail- The California Trail made a split at one point and instead of the branch that went to California the other branch turned northwest and went to Oregon.


The Journey Westward

  • John C. Fremont- led an official government expedition across the western territory in 1842.  He followed the trails of the Mountain Men and the Whitmans of the Oregon Trail.  He wrote very vivid accounts that romanticized the western frontier and gained wide publicity for the west.  Thousands of settlers would flock to the west over the next decade.

Treaty of Fort Laramie- As more settlers moved west, there was concern about the Native Americans occupying the land over which the pioneers would travel.  The government tried to restrict the Plains Indians by creating the Treaty of Fort Laramie in 1851.

  • The Treaty bound the Indians to territories away form the major trails.
  • However, the Indians clung to their nomadic way of life, pursuing the buffalo across the artificial boundaries set by the Treaty.