Battles of the War

The Battle of Contreras

The U.S. launched two major assaults on August 20, 1847, as part of General Winfield Scott’s sophisticated strategy to neutralize the 36,000-man army assembled by General Antonio Lopez de Santa Anna to defend Mexico City. The principal Mexican positions covered two roads heading to the city. A fortified Hacienda in the town of San Antonio covered the easternmost approach, while the town of San Angel covered the westernmost. Between them to the south lay a vast, seemingly impenetrable lava field, El Pedrégal.

General Gabriel Valencia, on the Mexican right flank, abandoned his assigned post and moved four miles down the road to the town of Contreras, placing this rough terrain between him and the Mexican left. A premature, ill-advised, and unsuccessful August 18 attack by generals Gideon Pillow and David Twiggs revealed American intentions to isolate and destroy Valencia. Santa Anna rushed Valencia reinforcements rather than recalling him to the more defensible positions at San Angel.

The next day, American scouts found a way to emerge from El Pedrégal a little farther north, thus cutting the road to Mexico City and isolating Valencia from additional reinforcements. Scott realized that once Valencia’s command fell, Pillow and Twiggs could race north to the Rio Churubusco and gain the rear of the Mexican forces facing the rest of the American army. Scott prepared to advance. 

At dawn on August 20, Pillow renewed his attack on Valencia’s front and elements of Twiggs’ command attacked the rear position of the Mexican force. Valencia’s 5,000-man army quickly melted away, a portion heading toward San Angel, the bulk simply quitting the field. By 6 a.m. Pillow and Twiggs started their troops toward the Rio Churubusco, and Scott ordered an attack against the Hacienda at San Antonio.