May 8, 1846

The opening battle between Mexican and U.S. forces in what shortly thereafter became the Mexican-American War, Palo Alto was a U.S. victory largely through the effective use of General Zachary Taylor’s artillery.

By the end of April 1846, Mexican and U.S. armies faced each other across the Río Grande near Matamoros. Taylor’s forces were at Fort Texas and the Point Isabel supply base on the north side of the river; the Mexicans were gathered at Matamoros.

Mexican cavalry had crossed the Río Grande above and below Fort Texas. General Anastasio Torrejón attacked a U.S. patrol under Captain Seth Thornton at Carricitos Ranch [1] and also a camp of Texas Rangers. Torrejón’s men later screened the crossing of approximately 4,000 infantry under General Mariano Arista about 13 miles below Fort Texas on April 30. Arista wanted to cut Taylor’s army off from its supply base at Point Isabel, but Arista had only two boats by which to ferry his troops, and this considerably delayed his crossing.

Learning of the Mexican activity and worried about protecting Point Isabel, Taylor left a small force at Fort Texas and force-marched to Point Isabel on May 1, arriving the following day after covering approximately 30 miles in 20 hours. Taylor’s weary men immediately began to fortify the meager defenses of Fort Polk at Point Isabel. By the time Taylor had passed, Arista had crossed his men and occupied the road between Taylor and Fort Texas. Arista sent General Pedro de Ampudia to besiege Fort Texas with a cannon barrage, which began at dawn on May 3.

After receiving a report from Texas Ranger Samuel Walker, who had slipped through the Mexican forces to confer with Major Jacob Brown, the commander at Fort Texas, Taylor moved out in the afternoon of May 7 with approximately 2,200 men, artillery, and 200 wagons. Knowing that Taylor was approaching, Arista recalled Ampudia’s men to join the pending battle.

Arista deployed his 4,000-man army across the road on an open grassy plain. The Mexican line was formed by midmorning on May 8. Interspersed between Arista’s infantry regiments were artillery batteries. The extreme left was anchored by Torrejón’s cavalry in a swampy thicket, and more cavalry was held in reserve behind the line in a tall stand of timber. General Arista rode along the line as the bands played and the colors and pennants fluttered in the breeze.

Taylor marched the final 12 miles in the morning. The day had became very hot as the U.S. troops came within a mile of the brightly colored Mexican army and gleaming lances and other weapons. Sitting sideways on his horse and spitting tobacco, Taylor casually deployed his infantry and artillery; his dragoons were held in reserve with the supply wagons. Arista allowed two U.S. scouts to ride to within 100 yards of his position and examine his line through field glasses. U.S. soldiers refilled their canteens from nearby ponds.

Approximately 2:30 P.M., Taylor began his advance. The Mexican gunners began firing from a range of 700 yards. The copper cannonballs simply rolled through the tall grass, and the men jumped over them. Taylor’s artillery, 10 to 20 yards in advance of the infantry, began firing at the dense mass of Mexican soldiers. Mexican gunners tried to knock out Taylor’s batteries. Captain Ulysses S. Grant recalled that the exploding U.S. shells “cut away through their ranks making a perfect road, but they would close up the interval without showing signs of retreat.” The fire from Major Samuel Ringgold’s Flying Artillery inflicted terrible losses on the Mexican left.

A charge by Torrejón attempted to sweep around Taylor’s right flank and strike the rear and supply wagons. The Mexican cavalrymen were slowed by the boggy ground, which allowed the U.S. 3rd and 5th Infantry Regiments time to run to the rear and challenge the attack. Torrejón tried to position two field pieces, but the accurate and constant fire of Ringgold’s artillery forced them back.

Despite the deadly effectiveness of the U.S. artillery, the Mexican troops held firm—Taylor reported that they were the “theme of comment and admiration.” The Mexican left was beginning to break under the heavy fire. A grass fire developed on Taylor’s left, and thick, blinding smoke covered the battlefield. Most of the firing stopped for approximately one hour. “The fire began to spread,” wrote Ramon Alcaraz. “Its sinister splendor illuminated the camp…and in which now were heard heart-rending groans of our wounded. As most of these were [wounded] from cannon-shot, they were horribly mutilated.”

During this interval, both Arista and Taylor adjusted the positions of their lines. Taylor tried to turn the Mexican left with Lieutenant Colonel Charles May’s dragoons, but the Mexican fire drove them back. Mexican battery fire killed Major Ringgold and forced the U.S. 4th Infantry to retreat. As the Mexicans began an assault on the U.S. left flank, Captain James Duncan’s light field batteries unleashed an unexpected enfilading fire that broke the attack.

Cannonading by both sides continued until dusk. The Mexican cavalry was turned back in a final charge, which began a general retreat on the Mexican right flank. The rest of the line fell back in good order to the edge of the woods. Taylor did not pursue because it was near nightfall. Search parties from both sides impartially brought in the wounded during the night. Surgeons amputated limbs long into the night.

The Mexican army was demoralized by the unexpected strength of the U.S. army, their deadly artillery, the frightful casualties, and the ineffectual leadership of their own generals. (Some soldiers even believed that Arista had wanted to lose to the U.S. army and was guilty of treason.) The battle was largely an artillery fight that was tactically a U.S. victory because Taylor had not retreated; strategically it was more of a draw because Arista still blocked the road to Fort Texas. The effective use of the U.S. Flying Artillery, [2] including firing at masses of men instead of at enemy artillery batteries, made the difference in the fight. Taylor’s casualties were approximately 55 killed, wounded, and missing; Arista’s, approximately 400, an indication of the artillery advantage that the United States had.

A volunteer soldier described the Mexican position on the battlefield a few months afterward as being a line of scattered bones and rags—many of the dead had not been buried.

The battlefield became a National Historic Site in June 1992. Recent archaeological surveys have identified major portions of the Mexican line through the recovery of buttons, badges, and other equipage.

[1] Skirmish at Carricitos Ranch, April 25, 1846

About 80 U.S. dragoons from General Zachary Taylor’s newly arrived army were attacked at Carricitos Ranch, Texas, on April 25, 1846, by General Anastasio Torrejón’s cavalry. It was this first military engagement that led President James K. Polk to proclaim that U.S. blood had been spilled on U.S. soil.

General Taylor moved his Army of Occupation from its winter camp at Corpus Christi, Texas, to the north bank of the Río Grande opposite Matamoros in the first few months of 1846. Hearing that a Mexican force had crossed the river, Taylor dispatched Captain Seth B. Thornton and 80 dragoons to check the river crossings on April 24. Against the advice of Chapita, his Mexican guide, Thornton pushed on the following day. While the dragoons were exploring the buildings of the abandoned Rancho de Carricitos, General Anastasio Torrejón’s Mexican cavalry closed the gates and opened fire on the trapped U.S. troopers from the cover of the surrounding thick chaparral. Eleven U.S. soldiers were killed and six were wounded. The survivors were sent across the Río Grande to Matamoros as prisoners of war. Torrejón sent one wounded U.S. soldier back to Taylor’s camp in an oxcart with a note stating that he could not adequately treat the soldier’s wounds.

This first major armed conflict between the Mexican and U.S. forces along the Río Grande gave Polk the opportunity to claim that “Mexico…has invaded our territory and shed American blood upon the American soil.” Two days later, the U.S. Congress declared war on the Republic of Mexico.

[2] Flying Artillery

One of the greatest advantages that the U.S. army enjoyed during the Mexican-American War was its Flying Artillery. These lighter, more mobile artillery pieces could be moved quickly across a battlefield and were critical to General Zachary Taylor’s early victories in northern Mexico.

The Flying Artillery started as an experimental battery organized by Major Samuel Ringgold in 1838, who enlarged on the concepts of Captain Robert Anderson. The guns could be quickly moved into forward positions or across a battlefield to wherever they were most needed. The success of the Flying Artillery was largely a result of the rigorous training of artillerymen, teamsters, and horses. Sometimes riding the horses and the caisson, the men would advance at a full gallop, unlimber, fire, remount, and move. Their constant movement made it difficult for enemy gunners to sight them as a target.

The Flying Artillery often fought from exposed forward positions and targeted masses of infantry and cavalry. These artillerists were some of the bravest men in the U.S. army and frequently took heavy losses. The artillery was highly effective at the Battle of Palo Alto on May 8, 1846, and cut huge holes in the Mexican ranks from as close as 100 yards. Ringgold was mortally wounded during the fight and died three days later. The Flying Artillery continued to torment the Mexican armies throughout the rest of General Zachary Taylor’s campaign in northern Mexico and throughout General Winfield Scott’s Veracruz–Mexico City campaign in 1847.

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