The Battle of Contreras:
On August 20, 1847, American forces attacked the entrenched Mexican army near the town of Contreras, just outside of Mexico City. The Mexicans, under the command of General Gabriel Valencia, had made camp a little too far from reinforcements, and American General Persifor Smith made them pay, launching a swift surprise attack at dawn. Valencia’s force was broken in minutes at the Battle of Contreras (also called the Battle of Padierna) and eliminated as a viable force for the defense of Mexico City. American General Winfield Scott followed the attack later in the day at the Battle of Churubusco, in which he gained a toehold in Mexico City itself.
The March to Mexico City:
Hostilities had broken out in 1846 between Mexico and the USA, mostly over Texas and the Americans' desire to gain California, New Mexico and other western Mexican territories. In spring of 1847, American General Winfield Scott
landed near Veracruz and began battling towards Mexico City, taking the city of Veracruz
and winning the crucial Battle of Cerro Gordo along the way. When Scott arrived outside of Mexico City in August of 1847, he saw the main approach to the city from the east was guarded by El Peñon, an imposing fortress. Scott decided to go around El Peñon and attack the city from the south and moved his forces accordingly.
Valencia and Santa Anna:
Mexican General Gabriel Valencia had an army of some 7,000 men, many of them well-trained and armed. Valencia was a political enemy of Antonio López de Santa Anna
, frequent president of Mexico and current commander of all Mexican forces. The two men detested one another to the point where Santa Anna had fought at Cerro Gordo without ordering Valencia to come support him. As the Americans moved to the south, Santa Anna ordered Valencia to hold a position at San Angel on the western edge of the city defenses: Valencia ignored him and instead took up a position at the Padierna ranch on a hill near the town of Contreras, about five miles away. It was a deliberate move by Valencia: he hoped to deal a decisive defeat to the Americans by himself, which would greatly enhance his political standing.
The Americans Move:
On August 19th, Scott made his move. He sent ahead General Gideon Pillow to pave the way through a lava field called the pedregal to the west: they did not know that this path would take them close to Valencia's imposing force. Pillow sent three divisions to the town of San Gerónimo, not knowing that this placed the men right between Valencia and Santa Anna. Fortunately for the Americans, General Persifor Smith noticed this and reinforced the men at San Gerónimo before Santa Anna and Valencia could crush them between them.
Skirmishing and Drinking:
Into the late evening on August 19, American and Mexican forces skirmished near Valencia’s position. Valencia easily held off the Americans, which caused him to declare a great victory and drink into the night with his officers, all of whom were promoted on the spot. Meanwhile, during the night, Santa Anna retreated from nearby San Angel, missing a chance to crush a significant part of the American force and placing him too far away to come to Valencia’s aid the next day. It is unknown why Santa Anna did so: he may have wanted to embarrass Valencia or he may have sincerely felt that his forces would be needed elsewhere.
The Battle of Contreras:
General Smith, sensing that Valencia was in a weak position, arranged an attack at dawn. The Americans pretended to assault the hill from the south, but the main attack had gone around the hill to attack from the northwest. When all was said and done, Smith assaulted the hill from three sides. Valencia’s men, who were dismayed to see with the first light of day that Santa Anna had retreated to the city, fought for less than 20 minutes before breaking, fleeing and surrendering.
Legacy of the Battle of Contreras:
General Scott estimated that 700 Mexicans were killed at Contreras and 813 were taken prisoner, including four generals (but not including Valencia, who had escaped and then fled upon hearing that an irate Santa Anna had ordered him shot on sight). About 60 American soldiers were killed, and another 200 or so wounded.
With Valencia's force effectively destroyed, Mexican troops all along the front lost heart and broke, retreating across the bridge at Churubusco into Mexico City. The Americans followed, unwittingly falling into an unintended trap: the bridge and nearby convent were heavily fortified. That afternoon, Americans trying to cross into Mexico City would fight the Battle of Churubusco, famous in history for the spirited defense of the city put up by the St. Patrick's Battalion, a Mexican army unit comprised largely of Irish Catholic deserters from the American Army.
The Battle of Contreras is a historical footnote to the more important Battle of Churubusco, but it is nevertheless significant in its own right as well. The antagonism between Valencia and Santa Anna was typical of Mexican leadership during this time: many Mexican political/military leaders hated each other so much that they were unable even to unite to face a common enemy. The American officers, on the other hand, launched a swift, co-ordinated attack involving several generals and their troops.
Eisenhower, John S.D. So Far from God: the U.S. War with Mexico, 1846-1848. Norman: the University of Oklahoma Press, 1989
Hogan, Michael. The Irish Soldiers of Mexico. Createspace, 2011.
Scheina, Robert L. Latin America's Wars, Volume 1: The Age of the Caudillo 1791-1899 Washington, D.C.: Brassey's Inc., 2003.
Wheelan, Joseph. Invading Mexico: America's Continental Dream and the Mexican War, 1846-1848. New York: Carroll and Graf, 2007.