Sebastian S.B.'s Mexican American War Timeline By MsOlson Period: Jan 1, 1845 to Jan 1, 1849 Mexican-American War Mar 1, 1845 Texas Admitted to the union The United States successfully accepts Texas from Mexico. Nov 1, 1845 US tried to buy land (Slidell and Polk) Predient Polk sends John Slidell to Mexico with instructions to buy California and New Mexico. Mar 1, 1846 US trooops stationed at disputed border U.S. General Taylor moves his troops past the Nueces river, moving into disputed territory. May 1, 1846 US declares war President Polk asks the U.S. Congress to declare war on Mexico. Sep 20, 1846 Battle of Monterrey U.S. troops, in an effort to cut off Northern Mexico, conquer the city of Monterrey. Sep 14, 1847 Mexico City Surrendered The U.S. army conquers and occupies Mexico CIty Feb 2, 1848 Treaty of Guadelupe Hidalgo Mexico signs a treaty with the U.S. which makes Mexico cede 55% of its territory to the U.S. in exchange for fifteen million dollars.