The Mexican Cession
The Mexican Cession was the vast territory Mexico gave to the United States under the Treaty of Guadalupe Hidalgo in 1848, following the US victory in the Mexican-American War. This land transfer included present-day California, Nevada, Utah, Arizona, and parts of New Mexico and Colorado, adding 525,000 square miles to the United States and fulfilling the nation’s Manifest Destiny dream of reaching the Pacific Ocean. This Grade 8 history topic from Pengi Social Studies covers how the acquisition of this enormous territory immediately reignited the explosive debate over whether slavery would expand into the West.
Key Concepts
The war ended with the U.S. victory and the signing of the Treaty of Guadalupe Hidalgo in 1848. Under this treaty, Mexico was forced to cede (give up) 55% of its territory to the United States.
This vast land acquisition is known as the Mexican Cession . It included present day California, Nevada, Utah, Arizona, and parts of New Mexico and Colorado. While the U.S. achieved its dream of stretching to the Pacific Ocean, the acquisition of this new land immediately reignited the explosive debate over whether slavery would be allowed in the West.
Common Questions
What was the Mexican Cession?
The Mexican Cession was the large territory that Mexico ceded to the United States in the Treaty of Guadalupe Hidalgo in 1848, following the Mexican-American War. The cession included present-day California, Nevada, Utah, Arizona, and parts of Colorado, Wyoming, New Mexico, and Kansas—about 525,000 square miles in total.
What was the Treaty of Guadalupe Hidalgo?
The Treaty of Guadalupe Hidalgo was the peace treaty that ended the Mexican-American War in 1848. Under its terms, Mexico gave up 55% of its territory to the United States and accepted the Rio Grande as the border with Texas, in exchange for $15 million in payment from the US government.
Why did the Mexican Cession cause controversy?
The Mexican Cession reignited the slavery debate because the question of whether slavery would be allowed in the new territories had to be decided. California’s application for statehood as a free state threatened to tip the Senate balance against the South, leading directly to the Compromise of 1850.
What is Manifest Destiny and how does it relate to the Mexican Cession?
Manifest Destiny was the 19th-century belief that the United States was destined to expand westward from the Atlantic to the Pacific Ocean. The Mexican Cession fulfilled this dream by adding the vast southwestern territories to the US, giving the country a Pacific coastline and completing its continental expansion.
When is the Mexican Cession studied in Grade 8 history?
Grade 8 students study the Mexican Cession in the context of westward expansion and growing sectional tensions in the 1840s. It is a key cause-and-effect event that connects Manifest Destiny to the intensifying debate over slavery that eventually led to the Civil War.
Which textbook covers the Mexican Cession for 8th grade?
The Mexican Cession is covered in Pengi Social Studies Grade 8, Chapter 4: The Age of Jackson and Westward Expansion (1828–1850), where students trace how territorial expansion intensified the national crisis over slavery.