The answer is True.
The Treaty of Guadalupe Hidalgo was the agreement that ended the Mexican-American War. The United States was victorious in this war and returned received land from Mexico. This includes modern day states like California, Arizona, New Mexico, and parts of Colorado and Utah. All of this land the United States gained from this war is known as the Mexican Cession. Ultimately, the Mexican-American War resulted in Mexico losing more than half of their land to the United States.