Final answer:
The Treaty of Guadalupe Hidalgo ended the Mexican-American War, with the U.S. acquiring vast territories including parts of present-day southwestern states, and paid Mexico $15 million plus debt assumption.
Step-by-step explanation:
The Treaty of Guadalupe Hidalgo ended the Mexican-American War in February 1848. The terms of the treaty ceded a vast territory to the United States, including the modern-day states of California, Arizona, New Mexico, Texas, Utah, Nevada, and parts of Colorado and Wyoming, totaling about 525,000 square miles. In return, the United States agreed to pay Mexico $15 million and assume American claims against Mexico, which were about $3.25 million. This acquisition significantly expanded U.S. territory and was a pivotal event in the Westward expansion associated with Manifest Destiny.