President Polk wanted to buy the areas known as New Mexico and California. He thought that those areas might be for sale since those were thinly settled. Those areas belong to Mexico so, Polk sent a representative to try to buy those lands.
The huge areas known as California and New Mexico are thinly settled so, Mexico might sell us. Go and try to buy those lands from Mexico!
Mexican officials refused to even see the representative that Polk sent.
Why does the U.S want most of our land?
We're not meeting with the representative that U.S sent!
This is over the limits!!
There is just no way we are selling our land!
The relationship between Mexico and U.S went sour over the argument about the border in Rio Grande. On April 25, 1846, the mexican soldiers shot the U.S soldiers who were patrolling along the Rio Grande and this gives Polk the excuse that he has been waiting for. Then after Polk gave a speech about the shooting, the congress declared war on Mexico.
You shed American blood on the American soil!
You Americans are greedy!!
General Stephen Kearny led the army to New Mexico after the congress declared war on Mexico and his army took control of New Mexico without firing a shot. Meanwhile, a group of Americans led the explorer John C. Fremont launched a rebellion against Mexican rule in California and they jailed the Mexican commander of Northern California General Mariano Guadalupe. Then when Kearny reached California, he joined with the rebels. Just like this, all California is under American control within weeks.
Yep. California is ours now!
We did it!!!
John C. Fremont
The forces led by Zachary Taylor(American) and Santa Anna(Mexican) battled in Northern Mexico and no one won. A month later the American forces led by General Winfield Scott battled with Mexicans again but this time the Americans captured Mexico City. So, by September 1847, the Mexico City was already under control of U.S.
The Mexico City is the property of U.S from now on!!
There were arguments about buying those lands from Mexico but overall U.S got a lot of useful lands for $15 million. This is how the Mexican Cession became a part of U.S.
Early in 1848, Mexico and U.S signed a treaty called the Treaty of Guadalupe Hidalgo. In the treaty, Mexico agreed to give up Texas and the vast region called "Mexican Cession". The U.S agreed to give $15 million in return and promised to protect the Mexicans living in those areas. The area included the present day states of California, Nevada, Utah, Arizona, and New Mexico, as well as parts of Colorado and Wyoming
Treaty of Guadalupe Hidalgo *Mexico will give up Texas and Mexican Cession *U.S will pay $15 million for the land *U.S will protect the Mexicans living in the area