Roger Champagne's Mexican American War Timeline By MsOlson Jun 16, 1845 Texas Admitted to the Union The U.S has Texas annexed and addmited to the Union. Nov 1, 1845 US Tried to Buy Land (Sidel and Polk) President Polk tells John Sidel to go to Mexico City to buy California and New Mexico from them. Mar 1, 1846 US Troops Stationed at Disputed Border Taylor's Army marches South to the Rio Grande, the land that both the US and Mexico claim to be thiers. May 1, 1846 US Declares War President Polk asks Congress to declare war. Congress says yes and gives Polk ten million dollars and fifty thousand volenteers for the war. May 8, 1846 US Victory at Palo Alto Taylor's Army has victory at Palo Alto against Genral Mariano Arista and drives him back across the Rio Grande. Sep 14, 1847 Mexico City Surrendered The US captures Mexico City. Feb 2, 1848 Treaty of Guadelupe Hidalgo The Treaty is made by negotiators and is brought to congress for them to ratify it.