Manifest Destiny: Manifest Destiny was the belief that it was America's destiny to expand its territory from coast to coast. It fueled westward expansion ideologies during this time.
Oregon Territory: The Oregon Territory refers to an area in the Pacific Northwest that was jointly occupied by Britain and the United States until a treaty in 1846 established American control over present-day Oregon, Washington, Idaho, and parts of Montana and Wyoming.
Gadsden Purchase: The Gadsden Purchase was another land acquisition made by President Franklin Pierce in 1853 when he purchased a strip of land (present-day southern Arizona and southwestern New Mexico) from Mexico. It aimed at securing a route for a transcontinental railroad.