In April 1847, U.S. General Winfield Scott moved his army away from Vera Cruz and down the national road toward the interior. Mexican forces under General Antonio Lopez de Santa Anna occupied the strategic mountain pass of Cerro Gordo to block the way. The collision of these two armies on April 18 began a string of American victories that lead, ultimately, to the capture of Mexico City.
Santa Anna made his stand at a point where the national road climbed the highlands near Jalapa by traversing a narrow defile dominated on the west by two major hills, La Atalaya and El Telégrafo. Twelve thousand Mexican troops dug in to block the road and waited for the Americans. The vanguard of the 10,000-man U.S. force arrived on April 11, and scouts sized up the enemy position. They concluded that a costly frontal assault was the only option until an April 17 reconnaissance by Captain Robert E. Lee revealed that Santa Anna had trusted the terrain on his left to be impassible, and therefore had only lightly defended that approach.
On April 18, Scott ordered General David Twiggs to lead 7,000 men around the Mexican left along the path discovered by Lee, while a smaller force of about 3,000 men under General Gideon Pillow demonstrated against the Mexican front. General Santa Anna, alerted to the American plan by a U.S. deserter, repositioned his forces to intercept Twiggs’ attack. The Americans still worked their way around the Mexican line, cut off their line of retreat, and captured their camps. Santa Anna’s forces, fearing encirclement, fled. U.S. troops killed or wounded an estimated 1,000 Mexican soldiers and captured another 3,000, as well as the artillery, baggage, and supplies of Santa Anna’s army. U.S. losses were a little more than 400.