Battle of Palo Alto

Battle of Palo Alto, first battle of the Mexican War, fought near present-day Brownsville, Texas, at the southern edge of the state. After the United States had annexed Texas, the American general Zachary Taylor advanced to the Río Grande, which the U.S. considered the southern border of Texas. The Mexican government considered this Mexican territory, and the Mexican general Mariano Arista crossed the Río Grande and was defeated in a battle with Taylor's army at Palo Alto on May 8, 1846. President James K. Polk announced that Arista had invaded American territory, and the U.S. Congress declared war.