Battle of Molino del Rey

September 8, 1847

The Battle of Molino del Rey was fought on September 8, 1847, between the United States and Mexico, during the Mexican-American War. The outcome of the battle was an American victory.

Battle of Molino del Rey, 1847, US Attack, Mexican American War

Attack upon the Molino by Carl Neber, 1851. Image Source: Yale University Library.

Battle of Molino Del Rey Facts

  • Date — September 8, 1847.
  • Location — 2 miles south of Mexico City.
  • Opponents — United States of America and Mexico.
  • American CommanderWinfield Scott.
  • Mexican Commander — Antonio León.
  • Winner — The United States won the Battle of Molino del Rey.
Winfield Scott, General, Mexican-American War
General Winfield Scott (USA). Image Source: Yale University Library.

Key Moments

  • Antonio López de Santa Anna, President of Mexico, broke the terms of an armistice that he had agreed to with General Winfield Scott following the Battle of Churubusco.
  • Scott was told the Mexicans were using Molino del Rey as a foundry to make cannons, which would be used to defend Mexico City against American forces.
  • On the morning of September 8, Major General William Worth led three columns in an attack on Molino del Rey.
  • After intense fighting, the Mexicans were pushed out of Molino del Rey and Casa Mata
  • American forces did not find any cannon at Molino del Rey.

Battle of Molino del Rey Significance

The Battle of Molino del Rey was important to the outcome of the Mexican-American War because American forces won the battle. Following the victory, American forces prepared to assault the Mexican defenses at Chapultepec Castle (September 12–13, 1847).

Battle of Molino del Rey History

On August 21, following the Battle of Churubusco, the two armies agreed to an armistice, but negotiations failed when U.S. leaders realized Santa Anna was simply stalling for time and preparing to resume hostilities.

The Battle of Molino del Rey occurred on September 8, 1847, during Major General Winfield Scott’s Mexico City Campaign. It was fought near Chapultepec Castle, two miles southwest of Mexico City.

Mexican Defenses at Molino del Rey — The King’s Mill

El Molino del Rey, also known as the “King’s Mill,” was a key piece of the defenses set up by  Mexican General Antonio López de Santa Anna to protect Mexico City. During the armistice period, Mexican engineers turned Molino del Rey into a strong defensive fortification, under the command of Brigadier General Antonio León. However, León placed Mexican troops and artillery were placed in front of buildings, instead of inside them for protection.

Antonio Lopez de Santa Anna, Portrait, Illustration
Antonio López de Santa Anna. Image Source: New York Public Library Digital Collections.

Scott Targets El Molino del Rey

Intelligence reports led General Scott to believe Molino del Rey was being used as a foundry to manufacture heavy artillery for the defense of Mexico City. Scott responded by issuing orders to Major General William Worth to force the Mexicans out and seize the foundry.

Worth led approximately 3,400 troops, including 7 infantry regiments, 2 dragoon regiments, and various artillery units. León’s army consisted of 3 light infantry regiments, 3 regular infantry regiments, and 6 artillery pieces, which were operated by men from the San Patricio Battalion.

The members of the San Patricio Battalion were mostly Irish immigrants, many of whom had deserted or defected from the U.S. Army. Because of that, many Americans viewed the San Patricios as traitors.

The Battle of Molino del Rey Begins

Worth organized his forces into three columns and prepared to assault Molino del Rey. However, the attack was disorganized and poorly planned. When Worth’s men advanced on the mill, they were met with heavy fire from Mexican muskets and artillery. The Americans suffered heavy casualties and fell back to prepare for a second assault.

Worth reorganized his forces and shifted some of his artillery batteries to his right, targeting the entire left wing of León’s defenses

Meanwhile, a Mexican cavalry unit arrived to reinforce Molino Del Rey. They were unsuccessful because American dragoons engaged them and drove them off.

Second Assault

Worth launched the second assault on Molino del Rey, which forced the Mexicans to take shelter in the mill. However, after two hours, the Mexicans were forced out of the mill. They also retreated from Casa Mata, a nearby fort.

Once the mill was secure, the Americans searched for cannons but found nothing more than a few gun molds.

Battle of Molino del Rey, 1847, Attack on Casa Mata, Mexican American War
This illustration depicts American forces attacking Casa Mata. Image Source: Yale University Library.

American Casualties

Americans suffered heavy casualties at the Battle of Molino del Rey. Around 3,400 Americans were involved and it is estimated 800 were killed or wounded.

Mexican Casualties

The Mexicans suffered approximately 2,000, casualties, including the death of General León.


Due to the heavy casualties, Worth was criticized for rushing into the attack and failing to gather more information about the strength of the Mexican forces. 

General Scott responded by taking more time to plan out his attack on Mexico City, and he decided to bombard Mexican forces at Chapultepec Castle first.

Following the battle, Scott moved toward Mexico City from the south, but it was nothing more than a diversionary tactic. Five days later, he moved into position to begin the bombardment of Chapultepec Castle.

Scott’s Official Report for the Battle of Molino del Rey

The following is General Winfield Scott’s official report of the Battle of Molino del Rey.

It was written to William L. Marcy, Secretary of War, on September 11, 1847, and sent to Washington, D.C. 

Note: Section headings and additional spacing have been added to improve the readability of the report.

September 11, 1847

Headquarters of the army,

Tacubaya, near Mexico, September 11, 1847.

Sir: — I have heretofore reported that I had, Aug. 24th, concluded an armistice with President Santa Anna, which was promptly followed by meeting between Mr. Trist and Mexican commissioners appointed to treat of peace.

Failed Negotiations

Negotiations were actively continued, with, as we understood, some prospect of a successful result up the 2d instant, when our commissioner handed in his ultimatum, (on boundaries,) and the negotiators adjourned to meet again on the 6th.

Santa Anna Prepares for Hostilities

Some infractions of the truce, in respect to our supplies from the city, were earlier committed, followed by apologies, on the part of the enemy. Those vexations I was willing to put down to the imbecility of the government, and waived pointed demands of reparation while any hope remained of a satisfactory termination of the war. But on the 5th, and more fully on the 6th, I learned that as soon as the ultimatum had been considered in a general council of ministers and others, President Santa Anna, on the 4th or 5th, without giving me the slightest notice, actively recommended strengthening the military defences of the city, in gross violation of the 3d article of the armistice.

On that information, which has since received the fullest verification, I addressed to him my note of the 6th. His reply, dated the same day, received the next morning, was absolutely and notoriously false, both in recrimination and explanation. I enclose copies of both papers, and have had no subsequent correspondence with the enemy.

Being delayed by the terms of the armistice more than two weeks, we had now, late on the 7th, to begin to reconnoiter the different approaches to the city, within our reach, before I could lay down any definitive plan of attack.

Mexican Forces at Molino Del Rey

The same afternoon a large body of the enemy was discovered hovering about the Molino del Rey, within a mile and a third of this village, where I am quartered with the general staff of Worth’s division.

Rumors of a Cannon Foundry

It might have been supposed that an attack upon us was intended; but knowing the great value to the enemy of those mills, (Molino del Rey) containing a cannon foundry, with a large deposit of powder in Casa Mata near them; and having heard, two days before, that many church bells had been sent out to be cast into guns, the enemy’s movement was easily understood, and I resolved, at once, to drive him early the next morning, to seize the powder, and to destroy the foundry.

Another motive for this decision — leaving the general plan of attack upon the city for full reconnoissances — was, that we knew our recent captures had left the enemy not a fourth of the guns necessary to arm, all at the same time, the strong works of each of the eight city gates; and we could not cut the communication between the foundry and the capital without first taking the formidable castle on the heights of Chapultepec, which overlooked both and stood between.

Unpreprepared for the Attack

For this difficult operation, we were not entirely ready and moreover we might altogether neglect the castle, if as we then hoped, our reconnoissances should prove that the distant southern approaches to the city were more eligible than this southwestern approach.

American Forces

Hence the decision promptly taken, the execution of which was assigned to Brevet Major General Worth, whose division was reinforced with Cadwallader’s brigade of Pillow’s division, three squadrons of dragoons under Major Sumner, and some heavy guns of the siege train under Captain Huger of the ordnance, and Capt. Drum of the 4th artillery — two officers of the highest merit.

For the decisive and brilliant results, I beg to refer the report of the immediate commander — Major General Worth — in whose commendations of the gallant officers and men — dead and living — I heartily concur; having witnessed, but with little interference, their noble devotion to fame and to country.

Scott Sends Reinforcements

The enemy having several times reinforced his line and the action soon becoming much more general than I had expected, I called up, from the distance of three miles, first Major General Pillow, with his remaining brigade, (Pierce’s,) and next Riley’s brigade of Twiggs’ division — leaving his other brigade (Smith’s) in observation at San Angel. Those corps approached with zeal and rapidity; but the battle was won just as Brigadier General Pierce reached the ground, and had interposed his corps between Garland’s brigade (Worth’s division) and the retreating enemy.

Commendations for the Battle of Molino Del Rey

The accompanying report mentions, with just commendation, two of my volunteer aids — Major Kirby, paymaster, and Major Gaines, of the Kentucky volunteers, I also had the valuable services, on the same field, of several other officers of my staff, general and personal — Lieut. Col. Hitchcock; acting inspector general; Captain R.E. Lee, engineer; Capt. Irwin, chief quartermaster; Captain Grayson, chief commissary, Capt. H.L. Scott, acting assistant adjutant general; Lieut. Williams, aid de camp, and Lieut. Lay, military secretary.

Robert E. Lee, 1838, Portrait
Robert E. Lee, circa 1838. Image Source: Wikimedia.

I have the honor to be, sir, with high respect,

Your most obedient servant,


Battle of Molino del Rey APUSH

The Battle of Molino del Rey and the Mexican-American War are part of Unit 5: 1844–1877 of the AP US History curriculum.

Citation Information

The following information is provided for citations, including APA Style, Chicago Style, and MLA Style.

  • Article Title Battle of Molino del Rey
  • Date September 8, 1847
  • Author
  • Keywords Battle of Molino del Rey, Winfield Scott, William Worth, Antonio León, Casa Mata, Robert E. Lee, Gideon Pillow
  • Website Name American History Central
  • Access Date June 13, 2024
  • Publisher R.Squared Communications, LLC
  • Original Published Date
  • Date of Last Update November 27, 2023