1. Mexican Cession & the Mexican American War (1846 - 1848) military conquest

2. War in Texas  Mexico = Texas annexation, act of war  No border ever agreed upon (Dispute over Rio Grande)  While patrolling the Rio Grande, American Soldiers killed  Declare war on Mexico

3. New Mexico and California  Polk determined to have California and New Mexico  Areas first colonized by Spain, then became Mexican territories  Both areas fell during Mexican war  Invades Mexico  http://www.youtube.com/watch?v=XuC-ucEZEJ4

4. Treaty of Guadalupe Hidalgo  Mexico gives up Texas and Mexican Cession (Half of ALL its territory)  U.S. pays Mexico and promises to protect Mexicans in Texas  A few years later, Gadsden Purchase (1853) – bought from Mexico to complete sw border for transcontinental RR