What was the land gained by the united states in the mexican-american war called?

The Mexican-American War was fought between the United States and Mexico from 1846 to 1848. It was primarily over the territory of Texas.

Background

Texas had been a state of the country of Mexico since 1821 when Mexico gained its independence from Spain. The Texans, however, began to disagree with the government of Mexico. In 1836, they declared their independence from Mexico and formed the Republic of Texas. They fought several battles including The Alamo. In the end, they gained their independence and Sam Houston became the first President of Texas.

Texas Becomes a US State

In 1845, Texas joined the United States as the 28th state. Mexico didn't like that the United States took over Texas. There also was a disagreement over the border of Texas. Mexico said the border was at the Nueces River while Texas claimed the border was further south at the Rio Grande River.

War with Mexico

President James K. Polk sent troops to Texas to protect the border. Soon Mexican and US troops were shooting at each other. On May 13, 1846 the United States declared war on Mexico.

Mexican-American War Overview Map
By Kaidor [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)],
via Wikimedia Commons
(Click picture to see larger view)

The Mexican army was led by General Santa Anna. The US forces were led by General Zachary Taylor and General Winfield Scott. General Taylor's forces were the first to engage the Mexican army. They fought an early battle at Palo Alto where the Mexicans were forced to retreat.

General Taylor advanced into Mexico fighting battles at the city of Monterrey and a mountain pass called Buena Vista. At the Battle of Buena Vista, Taylor and 5,000 troops were attacked by 14,000 Mexican troops led by Santa Anna. They held off the attack and won the battle despite being outnumbered.

Capture of Mexico City

President Polk didn't trust Zachary Taylor. He also considered him a rival. Instead of reinforcing Taylor's troops to capture Mexico City, he sent in another army led by General Winfield Scott. Scott advanced on Mexico City and captured it in August of 1847.

With the United States in control of their capital city and much of the country divided, the Mexicans agreed to a peace treaty called the Treaty of Guadalupe Hidalgo. In the treaty, Mexico agreed to the border of Texas at the Rio Grande. They also agreed to sell a large area of land to the United States for $15 million. Today this land makes up the states of California, Nevada, Utah, and Arizona. Portions of Wyoming, Oklahoma, New Mexico, and Colorado were also included.

When war broke out against Mexico in May 1846, the United States Army numbered a mere 8,000, but soon 60,000 volunteers joined their ranks. The American Navy dominated the sea. The American government provided stable, capable leadership. The economy of the expanding United States far surpassed that of the fledgling Mexican state. Morale was on the American side. The war was a rout.

Polk directed the war from Washington, D.C. He sent a 4-prong attack into the Mexican heartland. John Fremont and Stephen Kearny were sent to control the coveted lands of California and New Mexico. Fremont led a group of zealous Californians to declare independence even before word of hostilities reached the West. The "Bear Flag Republic" was not taken seriously, but Fremont and his followers did march to Monterey to capture the Mexican presidio, or fort. By 1847, California was secure.

The original Treaty of Guadalupe Hidalgo was printed in two columns, the English translation on the left and the Spanish on the right.

Meanwhile, Kearny led his troops into Santa Fe in August of 1846 causing the governor of New Mexico to flee. The city was captured without a single casualty. Soon he marched his army westward across the desert to join Fremont in California.

The attack on Mexico proper was left to two other commanders. Zachary Taylor crossed the Rio Grande with his troops upon Polk's order. He fought Santa Anna's troops successfully on his advance toward the heart of Mexico. Winfield Scott delivered the knockout punch. After invading Mexico at Vera Cruz, Scott's troops marched to the capital, Mexico City. All that remained was negotiating the terms of peace.

The Mexican Cession

Was the United States justified in taking half of Mexico's territory in the Treaty of Guadalupe Hidalgo?

Yes

No

At home, the Whigs of the north complained bitterly about the war. Many questioned Polk's methods as misleading and unconstitutional. Abolitionists rightly feared that southerners would try to use newly acquired lands to expand slavery. Antiwar sentiment emerged in New England much as it had in the War of 1812. Writer Henry David Thoreau was sentenced to prison for refusing to pay the taxes he knew were used to fund the war effort. His essay, Civil Disobedience, became a standard of peaceful resistance for future activists.