Harrison G Mexican American War Timeline By MsOlson Period: Jan 1, 1845 to Jan 1, 1849 Mexianc American War Mar 1, 1845 Texas Admitted to the Union America accepts Texas from Mexico and adds it to the Union Nov 17, 1845 US Tried to Buy Land (Sidel and Polk) Polk sends John Slidell to Mexico to buy New Mexico and California, but the Mexican press found out. Mar 6, 1846 US Troops Stationed at Disputed Border General Taylor's army marches to Rio Grande where the territory is both Mexico's and the United States's. May 8, 1846 US Declares War Taylor requests in a letter to Polk to ask Congress to declare war on Mexico. May 9, 1846 US Victory at the Battle of Palo Alto Taylor's army wins and drives Mexicans back across the Rio Grande. Sep 14, 1847 Mexico City Surrendered U.S. occupies and takes over Mexico City. Feb 2, 1848 Treaty of Guadalupe Hidalgo Treaty of Guadalupe Hidalgo is signed by negotiaters and is rushed to Washington D.C.