Although westward expansion officially began as limitations were removed through the birth of the United States and heightened with the Louisiana Purchase and a treaty with Spain that gave us Florida and the Gulf Coast along with the Oregon Territory, expansion reached its height in the 1850s. The frontier had reached across the Rocky Mountains to California, which was admitted as a state in 1850, and the large areas in between had been settled in some form. Starting with the Monroe Doctrine, stating that no European power should usurp any more North American land, Americans emigrated westward with their idea of Manifest Destiny. The way west was paved by agriculture, extending the reaches of Cotton, Sugar, and Tobacco into the new frontier. Land could be had cheap, $1.25 an acre in 1820, down to simply settling on it in 1860. Trees were cleared and farms were built, agriculture being the main focus of settlers.
Of course this lead to major controversy, stemming from sectional views of the North and South with regards to what else, slavery. The westward movement of Southern agriculture brought slaves with it. The North made its best effort to prevent this. The Missouri Compromise of 1820 admitted Missouri as a slave state and Maine as a free state, lowering tensions for a short period. Soon after, two states would be admitted simultaneously in order to keep the balance. The Kansas-Nebraska act, authored by Stephen Douglas and passed in 1854, brought the idea of popular sovereignty to the table, and with it came great violence between Northern and Southern settlers that rushed to the states to vote for their way to prevail. This would eventually lead to the South determining that there could be no other way to preserve their beloved institution than to secede.
Sources:
1. http://www.let.rug.nl/usa/outlines/history-1954/westward-expansion-and-regional-differences.php
2. www.ushistory.org/us/31a.asp
Of course this lead to major controversy, stemming from sectional views of the North and South with regards to what else, slavery. The westward movement of Southern agriculture brought slaves with it. The North made its best effort to prevent this. The Missouri Compromise of 1820 admitted Missouri as a slave state and Maine as a free state, lowering tensions for a short period. Soon after, two states would be admitted simultaneously in order to keep the balance. The Kansas-Nebraska act, authored by Stephen Douglas and passed in 1854, brought the idea of popular sovereignty to the table, and with it came great violence between Northern and Southern settlers that rushed to the states to vote for their way to prevail. This would eventually lead to the South determining that there could be no other way to preserve their beloved institution than to secede.
Sources:
1. http://www.let.rug.nl/usa/outlines/history-1954/westward-expansion-and-regional-differences.php
2. www.ushistory.org/us/31a.asp