Buena Vista, battle of, military engagement in the Mexican War, fought Feb. 22-23, 1847. The battle site was just S of Saltillo, Coahuila, in Mexico. Gen. Zachary Taylor, disobeying orders from the U.S. government, had advanced here. Gen. Santa Anna, having gathered a Mexican army, made a long march north and, attacking Taylor's forces furiously, outflanked them. The fighting was hard and at the end of the second day seemed a drawn battle, but on the night of Feb. 23 the Mexican army withdrew, leaving Taylor in control of the north of Mexico.