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Westward Expansion: Summary and Timeline
Westward Expansion is the era in the first half of the nineteenth century that saw a rapid increase in the size and scope of the territory of the United States. Beginning with the Louisiana Purchase in 1803 to the cession of the southwestern territories from Mexico in 1848. The term Westward expansion specifically refers to the expansion of territory within the North American continent, as the United States continued to expand with territorial acquisitions in the 1860s and 1890s. Below is a westward expansion timeline and description of each expansion.
Fig. 1 - This map from the United States Department of the Interior shows the territorial expansion of the United States and the dates the territories were acquired
| Event | Description |
The Louisiana Purchase (1803) |
|
The Annexation of Florida (1819) |
|
Westward Expansion in the 1840s
The 1840s saw the next phase of rapid expansion of the territory of the United States: The Annexation of Texas in 1845, the acquisition of the Oregon Territory in 1846, and the cession of the southwest from Mexico in 1848.
The Annexation of Texas
Since the Adams-Onis Treaty in 1819, the territory of Texas was firmly in the hands of Spain and then Mexico after its independence from Spain in 1821. However, in 1836, Texas declared itself independent from Mexico and began petitioning the United States for statehood. The migration of American settlers into Texas fostered this independence movement. Mexico sent an army to quell the rebellion but was defeated by Sam Houston, and independence was granted.
Fig. 2- A portrait of President James K. Polk, who oversaw the Mexican American War and the annexation of Texas, the cession of the southwest, and the Oregon Treaty
What followed was nearly a decade of political issues and discourse over the statehood of Texas. The issue of Texas became a point of contention between the Whig Party which opposed the annexation, and the Democratic Party in favor. The main problem was slavery. In 1820, Congress passed the Missouri Compromise, establishing a boundary of which territories could have slaves and which could not. Northern Whigs feared Texas could create several slave states, upsetting the political balance in Congress.
Nevertheless, by 1845 the Democrats won out, and on his last full day in office, President John Tyler accepted the Texas annexation. His successor, President James K. Polk, upheld the annexation. Though the annexation was resolved, border disputes continued between the United States and Mexico, erupting in the Mexican American War in 1846.
The Oregon Treaty (1846)
After the War of 1812, Britain and the United States negotiated a northern border between British-held Canada and the United States along the 49-degree line of latitude to the Rocky Mountains. The region of the Rocky Mountains was jointly held by both nations, allowing for passage throughout.
Over the decades, however, this deal became less attractive to both nations as the region's resources became more accessible and valuable. Negotiations began in the early 1840s, but Britain held firm to wanting the borderline to continue the 49-degree line. In contrast, American expansionists wanted a border farther north along the 54-degree line. In June 1846, the U.S. and Britain signed the Oregon Treaty, establishing the northern border as the 49-degree line to the Pacific Ocean.
The outbreak of the Mexican American War forced the Americans to fold on their demands to Britain, as President Polk did not wish to have two wars at the same time.
Mexican Cession of the Southwest (1848)
In 1848, The United States defeated the Mexican Army, and the Mexican American War ended. The Treaty of Guadalupe Hidalgo ended the war. In this treaty, Mexico ceded all claims to Texas, created a southern border along the Rio Grande, and Mexico gave up claims of Utah, Arizona, New Mexico, California, Nevada, and parts of Oklahoma, Colorado, Kansas, and Wyoming to the United States.
Is it Destiny?
Near the conclusion of the Mexican American War, the term Manifest Destiny is coined in the American news media. This term is used to define the growing American ideology that it is the destiny of the United States to control the territory of North America from the Atlantic to the Pacific. This ideology is bolstered by the rapid annexation and claims of territory, to the point that many Americans felt it was “God-given,” that if God did not want the United States to have this land, then the U.S. would have lost the Mexican American War, the War of 1812, and would not have allowed the successful negotiations of so many favorable treaties. Manifest Destiny would be a foundation for foreign policy until the twentieth century.
Fig. 3 - "American Progress" by John Gast encapsulates the images and imagination of Westward Expansion in the 1800s.
Causes of Westward Expansion
Manifest Destiny was not a cause of Westward Expansion, as by the time it was used, the expansionist movement was already occurring. The causes of Westward Expansion were mainly economic factors of the western lands and technological changes that allowed for quick adaptations to the new regions.
Causes of Westward Expansion | |
Economic: Many aspects of the west brought migrants seeking to better themselves economically. |
|
Technology: rapidly changing and improving technological innovations allowed for mass migration into the west, but also the success of an industry to sustain populations in the west. |
|
The Effects of Westward Expansion
With its vast economic opportunities, Westward Expansion reaffirmed to many Americans that the United States was a land of opportunity. As more Americans moved west, the effects of westward expansion were beginning to be felt throughout American society.
By the end of the Mexican American War, the United States controlled all territory in North America from the Atlantic to the Pacific Oceans, from the Gulf of Mexico and the Rio Grande to the 49-degree latitude.
These new territories gave the United States access to vast amounts of natural resources and gave economic opportunities to millions of Americans. It also brought in hundreds of thousands, if not millions, of other immigrants seeking an opportunity. Thousands of Mexican migrants moved into the Southwest to work on cattle ranches, farms, and mines. Thousands of Chinese immigrants came to work on railroads. The lure of new opportunities brought new European migrants to the shores of the United States. In reaction, in the mid to late 1800s, the United States passed discriminatory immigration laws.
Westward Expansion and Slavery
Ironically, the expansion sparked sectional conflict as the nation was unifying vast territories. The debates over whether territories should be allowed to have the institution of slavery revived old southern fears of congressional and federal power. Throughout the expansion era, Congress tried to quell these fears and attempted to find a compromise. Legislation such as the Missouri Compromise of 1820, which designated a line of demarcation between what territories could and could not have slaves, held the nation together as pro-slavery and abolitionist movements grew. The annexation of Texas in 1845 brought up the issue again, as Northern abolitionists felt that many slave states could be created from the territory. Balanced by the admission of Oregon territory as a free region, the issue was only pushed aside until the subsequent territorial dispute: The Kansas-Nebraska Act of 1854.
Fig. 4- A map of the Kansas-Nebraska Act.
By this time, the territorial boundaries of the United States were settled, the question no longer being one of a balance of power, but now the actual discussion of slavery in the nation had to take place. The Kansas-Nebraska Act repealed the policy of congressional balance between slave and free states, allowing each new state to vote on whether or not the territory would be free of slavery. Triggering a series of events that would see the eruption of the American Civil War in less than six years.
For all its economic benefits, Westward Expansion had the unintended consequence of being one of the main catalysts of the American Civil War, as the strain of expansion pressed on the economic and social wound of slavery.
Westward Expansion - Key takeaways
- Westward Expansion is the era in the first half of the nineteenth century that saw a rapid increase in the size and scope of the territory of the United States.
- Beginning with the Louisiana Purchase in 1803 to the cession of the southwestern territories from Mexico in 1848.
- The causes of Westward Expansion were mainly economic factors of the western lands and technological changes that allowed for quick adaptations to the new regions.
- The debates over whether territories should be allowed to have the institution of slavery revived old southern fears of congressional and federal power.
- For all its economic benefits, Westward Expansion had the unintended consequence of being one of the main catalysts of the American Civil War, as the strain of expansion pressed on the economic and social wound of slavery.
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Frequently Asked Questions about Westward Expansion
what was the westward expansion?
Westward Expansion is the era in the first half of the nineteenth century that saw a rapid increase in the size and scope of the territory of the United States. Beginning with the Louisiana Purchase in 1803 to the cession of the southwestern territories from Mexico in 1848.
when did westward expansion begin?
For most historians, westward expansion begins with the Louisiana Purchase in 1803 by President Thomas Jefferson
how did westward expansion affect native americans?
Westward expansion saw the destruction of much of the indigenous peoples and tribes of North America. Many were forced to move off their homelands onto reservations, others assimilated into American society, and others were destroyed.
what was one of the positive effects of westward expansion?
These new territories gave the United States access to vast amounts of natural resources and gave economic opportunities to millions of Americans.
when did westward expansion end?
Most historians document the end of westward expansion with the end of the Mexican American War and the cession of the southwestern lands to the United States in the Treaty of Guadalupe Hidalgo and the finalization of the Oregon Treaty.
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