April 1846 – February 1848
The Mexican–American War, also known in the United States as the Mexican War and in Mexico as the United States intervention in Mexico, was an invasion of Mexico by the United States. It followed the 1845 American annexation of Texas, which Mexico still considered its territory because it refused to recognize the Treaties of Velasco, signed by President Antonio López de Santa Anna after he was captured by the Texian Army during the 1836 Texas Revolution. The Republic of Texas was de facto an independent country, but most of its Anglo-American citizens who had moved from the United States to Texas after 1822 wanted to be annexed by the United States.
April 1846
The Thornton Affair was a battle in 1846 between the military forces of the United States and Mexico 20 miles (32 km) west upriver from Zachary Taylor's camp along the Rio Grande. The much larger Mexican force defeated the Americans in the opening of hostilities, and was the primary justification for U.S. President James K. Polk's call to Congress to declare war. It is also known as the Thornton Skirmish, Thornton's Defeat, or Rancho Carricitos.