The Mexican-American War (April 1846–February 1848) was the result of the United States' annexation of Texas in 1845 and a border dispute over whether the Texas boundary ended at the Rio Grande River. The war—in which U.S. forces were consistently victorious—resulted in the United States' acquisition of more than 500,000 square miles of Mexican territory extending westward from the Rio Grande to the Pacific Ocean.

(1 hour 28 minutes)

Watch Streaming Video