To begin with, European migration to North America was limited to the East coast. However, as time went on, people began to move westward and crossed the Appalachian mountains. In 1820 the frontier sat at the Mississippi river but by 1830, people had puished the frontier even further to Texas. Large numbers of people moved west to attain religious freedom, most famously the Mormon people.
As the population in the West built up from the gold rush and railroad, some disagreement arose as laws and policy was still made in the East. The people in the West helped shift power and make people take notice of their needs as well. One issue that caused more problems than others is the idea of Manifest Destiny. This is where American people believed they had the right to own the lands of the West coast.
This belief led to Britain handing over control of Oregon as the cost to maintain control was too high. However things were not so simple for lands around Texas and Mexico. Texan people revolted and claimed United States citizenship, this lead to a brief war being fought between the two countries between 1846 and 1848. Everything was finally resolved as Texas became part of the United States of America.
Throughout this time, soldiers were routinely dispatched to the West by the United States Government due to disagreements with indigenous peoples. A westward movement of European migrants disrupted and overtook many traditional and indigenous lands leading to multiple skirmishes between the two peoples.
