Mexican-American War

The Battle of Monterrey resulted in a Mexican defeat when General Pedro de Ampudia's Army of the North was overcome by General Zachary Taylor's Army of Occupation, a combined force of U.S. Regulars, Volunteers, and Texas Rangers. The engagement demonstrated the operational reach of American forces into northern Mexico and affirmed Taylor's capacity to prosecute offensive operations against organized Mexican resistance. With Mexican forces numbering slightly more than the American contingent, the outcome reflected a significant reversal for Mexico's northern defensive posture during the early phase of the war.

The Battle of Resaca de la Palma was one of the opening engagements of the Mexican–American War. Fought on May 9, 1846, the battle saw General Zachary Taylor's force of approximately 1,700 U.S. troops engage General Mariano Arista's retreating Mexican Ejército del Norte, which numbered around 4,000. The U.S. victory drove Mexican forces out of Texas, consolidating American control over the disputed territory between the Nueces River and the Rio Grande that had been the immediate trigger of the war. Coming in rapid succession with other early engagements, the outcome strengthened Taylor's operational position in the theater and demonstrated that the smaller U.S. force could defeat a significantly larger Mexican army in open engagement.

U.S. victory

The Battle of Buena Vista, known in Mexico as the Battle of La Angostura, pitted a substantially outnumbered U.S. force of largely volunteer troops under General Zachary Taylor against a Mexican army more than three times its size under General Antonio López de Santa Anna near Saltillo, Coahuila. The outcome was contested: Santa Anna's forces withdrew from the field, taking captured cannons and flags as war trophies, while U.S. forces retained the ground, having anticipated a renewed Mexican assault the following day. Both sides claimed victory, reflecting the ambiguous operational result. The engagement demonstrated that U.S. volunteer forces could hold against a numerically superior professional army, while Mexico's withdrawal — despite inflicting and sustaining significant casualties — left the northern theater strategically inconclusive. Mexican casualties numbered over 1,000 against a U.S. force that never exceeded 4,750 men.

Churubusco was fought on August 20, 1847, as Santa Anna's army retreated from the Battle of Contreras, and its outcome placed U.S. forces within five miles of Mexico City, decisively opening the approach to the Mexican capital. The battle effectively broke organized Mexican resistance in the immediate theater, with Mexican casualties reaching 1,261 against a defending force of roughly 3,800. The engagement is also notable for the fate of the San Patricio Battalion, composed largely of U.S. deserters who had crossed to the Mexican side and made their last stand here. Following the American victory, 50 members of the battalion were executed by the U.S. Army — all but two by hanging — constituting the largest mass execution in United States history. The episode underscored the severity with which the U.S. Army treated wartime desertion, particularly when deserters bore arms against their former comrades.

The Battle of Contreras was one of the final engagements as Winfield Scott's forces advanced on Mexico City during the Mexican-American War. American forces surprised and routed the Mexican division under General Gabriel Valencia, who had disobeyed Santa Anna's orders regarding his forces' placement — a breakdown in Mexican command that contributed directly to the scale of the defeat, which cost the Mexican side 1,225 casualties. Despite being an overwhelming American victory, the battle generated little contemporary popular documentation. The engagement was immediately followed by the Battle of Churubusco the same day, placing Contreras within a rapid sequence of actions that steadily dismantled Mexican resistance on the approaches to the capital.

The Battle of Molino del Rey was one of the bloodiest engagements of the Mexican-American War, fought on the fringes of Mexico City as part of the broader American campaign to capture the Mexican capital. Despite making little progress during the engagement itself, American forces under Major General Winfield Scott were not repelled decisively enough to alter the campaign's trajectory. Mexican forces, though able to contest the attack, could not hold their positions long enough to prevent the fall of Mexico City one week later. The battle thus functioned as a costly but ultimately inconclusive preliminary to the final assault on the capital, illustrating the high toll of the urban approaches even when tactical results were limited. Ulysses S. Grant served as a captain during the engagement.

U.S. victory

U.S. victory

Artillery mobility and open terrain shaped early tactical outcomes.

The campaign demonstrated the difficulty of fighting through fortified cities.

Capture of the capital made Mexican defeat politically unavoidable.