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The Battle of Monterrey

September 21– 23, 1846 in Monterrey, California

Commanded by: Gen. Zachary Taylor
Strength: 6,220
Reported Casualties: 120 killed, 368 wounded, 43 Missing and Captured
Commanded by: General Pedro de Ampudia
Strength: abt 10,000
Reported Casualties: 367 killed and wounded, unknown Missing and Captured
Mexican Victory

The Battle of Monterrey (September 21–September 23, 1846) was an engagement in the Mexican-American War in which General Pedro de Ampudia and the Mexican Army of the North managed to fight US troops to a standstill at the important fortress town of Monterrey.

After a number of embarrassing defeats and near misses, the Army of the North attempted to retreat south and refit before engaging the seemingly unbeatable US forces under General Zachary Taylor. Near the old fortress town of Monterrey, General Pedro de Ampudia received orders from Antonio López de Santa Anna to retreat further to the city of Saltillo where Ampudia was to establish a defensive line. But Ampudia, who was hungry for victory and conscious that his men were nearing mutiny through constantly being forced to retreat, refused the order and chose instead to make a stand at Monterrey. Joining Ampudia at this engagement were an elite artillery unit, the largely Irish-American San Patricios (or the Saint Patrick's Battalion), in their first major engagement against US forces.

For three days, US forces attempted to take the city without success. Heavy Mexican resistance caused considerable losses in the US ranks, and the US artillery found itself incapable of penetrating the walls of the numerous fortresses and fortifications in the area. Finally, the invaders drew close enough to the city to use their only piece of siege artillery, a somewhat antiquated Napoleonic era 32-pound siege howitzer that began to hurl rounds into Monterrey's central plaza, panicking the local inhabitants.

On the night of the 23rd, a final US push to capture the city walls met with fierce resistance. The US line, near to cracking, began a somewhat disorganized retreat. At the same time, Zachary Taylor, determined to win the day, ordered his mortar to begin shelling indiscriminately. This act finally broke the back of the Mexican resistance and, with the US forces in full retreat, Ampudia ordered the white flag of surrender to be flown.

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The resulting armistice signed between Taylor and Ampudia had major effects upon the outcome of the war. Taylor was lambasted by Washington, where President James K. Polk insisted that the US army had no authority to negotiate truces, only to "kill the enemy". In addition, his terms of armistice, which allowed Ampudia's forces to retreat with battle honors and all of their weapons, were seen as foolish and short-sighted by some US observers.

For his part, some have argued that Ampudia had sown the seeds of defeat for Mexico. Many Mexican soldiers became depressed and disenchanted. In a well fortified, excellently supplied position, an army of twelve thousand Mexican soldiers had nearly defeated the US Army, only to be forced to surrender at their moment of triumph. Many felt that their generals simply did not want to win, and desertions and mutiny became widespread problems.


Major-General Zachary Taylor, at Monterey, Mexico, to Roger Jones,
Adjutant-General of the Army, at Washington, D.C. Dispatch communicating the
capitulation of the Mexican forces at Monterey.

Head-Quarters, Army of Occupation,

Camp before Monterey, September 25, 1846.

Sir: - At noon on the 23d inst., while our troops were closely engaged in the lower part of the city, as reported in my last despatch, I received by a flag a communication from the governor of the state of New Leon, which is herewith enclosed (No. 1.) To this communication, I deemed it my duty to return an answer declining to allow the inhabitants to leave the city. By eleven o'clock, P.M. the 2d division, which had entered the town from the direction of the Bishop's Palace, had advanced within one square of the principal plaza, and occupied the city up to that point. The mortar had, in the mean time, been placed in battery in the cemetery, within good range of the heart of the town, and was served throughout the night with good effect.

Early in the morning of the 24th I received a flag from the town, bearing a communication from General Ampudia, which I enclose, (No. 2,) and to which I returned the answer, (No. 3.) I also arranged with the bearer of the flag a cessation of fire until 12 o'clock, which hour I appointed to receive the final answer of Gen. Ampudia at Gen. Worth's headquarters. Before the appointed time, however, Gen. Ampudia had signified to Gen. Worth his desire for a personal interview with me, for the purpose of making some definite arrangement. An interview was accordingly appointed for one o'clock, and resulted in the naming of a commission to draw up articles of agreement regulating the withdrawal of the Mexican forces and a temporary cessation of hostilities. The commissioners named by the Mexican general-in-chief were Generals Ortega and Requena, and Don Manuel M. Llano, Governor of New Leon. Those named on the American side were Gen. Worth, Gen. Henderson, governor of Texas, and Colonel Davis, of the Mississippi volunteers. The commission finally settled upon the articles, of which I enclose a copy, (No. 4,) the duplicates of which (in Spanish and English) have been duly signed. Agreeably to the provisions of the 4th article, our troops have this morning occupied the citadel.

It will be seen that the terms granted the Mexican garrison are less rigorous than those first imposed. The gallant defence of the town, and the fact of a recent change of government in Mexico, believed to be favorable to the interests of peace, induced me to concur with the commission in these terms, which will, I trust, receive the approval of the government. The latter consideration also prompted the convention for a temporary cessation of hostilities. Though scarcely warranted by my instructions, yet the change of affairs since those instructions were issued seemed to warrant this course. I beg to be advised, as early as practicable, whether I have met the views of the government in these particulars.

I regret to report that Capt. Williams, Topographical Engineers, and Lieut. Terrett, 1st infantry, have died of the wounds received in the engagement of the 21st. - Capt. Gatlin, 7th infantry, was wounded (not badly) on the 23d.

I am, sir, very respectfully, your obedient servant,


Major-general, U.S.A. Commanding

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