| Term | Definition |
| Manifest Destiny | a belief by americans that we had a god given right to expand right in north america to the pacific, |
| Texas Revolution | War between Texas settlers and Mexico from 1835-1836 resulting in the formation of the Republic of Texas |
| James K. Polk | President of United States who had territorial aspirations, leading to conflict with Mexico, resulting in a war. |
| annexation | The adding of a region to the territory of an existing country. |
| Treaty of Guadalupe Hidalgo | treaty signed in 1848 by the Us and Mexico, ending the mexico war |
| Mexican Cession | all the land ceded to the U.S. a result of the Mexican war, it consisted of California, Nevada, Utah,and parts of Arizona, New Mexico, Wyoming, and Colorado |
| Mexican American War | 1846-1848 war with mexico, after Mexican refusal to sell California-New Mexico region, Polk sent troops and it ended w/ Treat of Guadalupe-Hidalgo |
| Gold Rush | a period from1848 to 1856 when thousands of people came to California in order to search for gold. |
| Oregon Trail | pioneer trail that began in missouri and crossed the great plains into the oregon country |
| Mormon Trail | In 1847, about 1,600 Mormons followed part of the Oregon Trail to Utah. They built a settlement by the Great Salt Lake. |