United States wanted over 500,000 square miles of new territory. These lands included Texas, the Mexican territories of New Mexico and Upper California. After the war was over, they became the American states of California, Arizona, and New Mexico, and comprised significant parts of Utah, Colorado, Nevada, and Wyoming. For the territory they lost, Mexico received $15 million, as well as $3,250,000 to settle American citizens' claims against the Mexican government. The United States Senate ratified the treaty on March 10, 1848. The Mexican Congress approved it on May 25. Texas had just gained it's independence
from Mexico and The U.S.A would not agree to incorporate them into
the Union. One of the reasons the refused to do so was because
“Northern political interests were against the addition of a new
slave state.” The Mexican government encouraged border raids.