On the evening of September 20, 1846, Maj. Philip Barbour of the 3rd US infantry sat overlooking the city of Monterrey and wrote in his journal. “There is quite a fire going on in the direction of the city.” Before finishing his passage for the night, Barbour, a veteran of Zachary Taylor’s earlier battles in the year, wrote, “I feel as calm and collected as if I were in the Astor House, having long since made up my mind that, during a time of war, my life is the rightful property of my country, and cannot be taken from me, or preserved, except by the fiat of the great God who gave it. And to His will, whatever it be, I am perfectly resigned.” Barbour closed his journal and prepared for the coming day.
Zachary Taylor, recently promoted to Maj. Gen. because of his success earlier in the spring, tasked his army with capturing Monterrey, the key to the inner heartland of Mexico. It would be rough-going, as Mexican forces turned the entire city into a veritable killing field, supported by a number of forts nestled into high hills whose batteries were trained towards the oncoming American forces.
To attack the city, Taylor split his force into columns. One column, under the command of Brig. Gen. William Worth, marched around the city starting on Sept. 20. Mexican cannon bombarded the column throughout the 20th, but caused little damage. Worth’s men bivouacked for the night still a few miles from their objective—the Saltillo Road, which, if captured, would seal Monterrey off from resupply or reinforcement.
In order for Worth’s flank attack to be successful, Taylor also planned for a diversionary attack to be launched straight at the city by his other subordinates, including Brig. Gen. David Twiggs and a division of volunteer troops under the command of Maj. Gen. William Butler.
Worth’s column made first contact with Mexican forces on the morning of Sept. 21. With the American regiments still in marching order, Mexican cavalry carrying dreadful lances hoped to slice the Americans to pieces. As they charged forward, however, the Mexican lancers ran straight into Worth’s screening force—mounted Texan Rangers. Armed with Colt pistols, the Texans’ repeating fire tore into the Mexicans, bloodying the lancers and sending them in retreat, keeping the road open for Worth.
With their route protected, the American infantry deployed to attack Federation Hill, a Mexican position that covered the Saltillo Road. Including infantry commanded by Captain Charles F. Smith (who, in 1862, died of an infected leg before his true potential could be reached serving for the Union), the Americans began to storm the hill. It proved hard-going, with the Americans forced to climb an almost 400-foot high slope, dotted with thorn bushes. As the Americans advanced, Mexican infantry sortied out to try and repulse the attack. Texas Rangers, armed with rifles, picked Mexican infantrymen off as the US regulars continued their advance at the point of the bayonet, pushing Mexicans back further and further towards Fort Soldado, a Mexican bastion guarding the other side of Federation Hill. Keeping the pressure up, Worth’s infantry soon captured Fort Soldado as well, sending the surviving Mexican soldiers into Monterrey or towards Independence Hill, in the distance. Their objectives accomplished, Worth’s men sat on their gains having suffered extremely light casualties in lieu of the fighting—one killed and a small handful of others wounded.
On the other side of Monterrey, while Worth’s men stormed Federation Hill, Taylor organized his diversionary attacks, which would prove far costlier to the American soldiers. From their camps, the American soldiers in the diversionary attacks had to cross “an immense plain in front of the town of more than two miles,” Colonel William Campbell, a volunteer commanding the 1st Tennessee Rifles, wrote.
Two US regular regiments—the 3rd and 4th Infantry—began the attacks against Monterrey. They were led by Lt. Col. John Garland (who would be killed at South Mountain in 1862 fighting for the Confederacy), who pushed them straight towards the city’s defenses.
The attack began to break down as Mexican artillery fire sliced into the regulars’ ranks. Closing their ranks, the regulars plunged into the streets of Monterrey, where a whole new horror began. Fighting with their linear formations, the US troops were wholly unprepared for the urban fighting that Monterrey forced them into. There were whole houses and blocks to be cleared in fighting that appears to a modern generation too familiar to actions in Fallujah, or Ramadi. On Sept. 21, 1846, however, the regulars were torn to pieces. “Monterrey was one of the U.S. Army’s few experiences with urban combat since the American Revolution,” historian Stephen A. Carney writes, “and the lack of expertise showed in the operations that followed.
Mexican soldiers reveled in the fighting. “The city is built almost entirely of stone and with very thick walls,” Ulysses S. Grant wrote in a letter home, and the Mexican forces used those defensive works to prove especially difficult to root out. From their protective works, they let loose scathing musketry volleys. Lieutenant Colonel Garland, wounded in the leg by a musket ball, later reported to General Taylor, “We soon found ourselves in narrow streets, where we received a most destructive fire from the three directions.”
The Americans continued to try and force their way into the street. Towards the front of the 3rd US, Major Philip Barbour led his men across a bridge and was then killed instantly with a ball to the chest. Nearby, the regiment’s colonel, W.W. Lear, was mortally wounded as a musket ball slammed into his face. Close to them, the 4th Infantry also took staggering losses.
Reinforcements arrived in the form of William Campbell’s Tennessee Rifles and another rifle regiment, this one from Mississippi and led by Colonel Jefferson Davis (future president of the Confederacy). These volunteers, joined by the bloodied regulars, set their targets on Fort Teneria, a bastion that would at least give Taylor’s men a toehold on the city. Forcing their way into the fort, the Americans managed to hold onto it, but costing even more losses.
Bloodied and bruised, pushing further into the town proved out of the question. Taylor’s men needed to regroup and count their loses before they could continue. So the bloody Sept. 21 came to a close—with Worth’s men in possession of Federation Hill and Fort Soldado while Twiggs, Butler, and others, had suffered dreadful casualties to capture just a couple of blocks leading into Monterrey.
After the Americans’ easy victories at Palo Alto and Resaca de la Palma, the first day’s action at Monterrey proved a stark wakeup call. “For West Pointers,” historian Christopher Dishman writes, “September 21, 1846, was one of the most tragic days in the academy’s history. Eleven graduates were killed in eastern Monterrey, six lost in the 3rd Infantry alone.” William Campbell, counting the losses amongst his Tenneseean riflemen, reported, “My killed on that day amounted to 27, and my wounded to 77.”
More would have to die before Monterrey’s fate was decided.
 Philip N. Barbour, Journals of the Late Brevet Major
Philip Norbourne Barbour (New York City: G.P. Putnam’s Sons, 1936), 108.
 William B. Campbell, Mexican War Letters of Col. William Bowen Campbell of Tennessee, Written to Governor David Campbell of Virginia, 1846-1847 (Nashville: Tennessee Historical Magazine, 1915), 143.
 The Papers of Ulysses S. Grant, Volume 01: 1837-1861, Edited by John Y. Simon, Southern Illinois University Press, 112.
 Christopher D. Dishman, A Perfect Gibraltar: The Battle for Monterrey, Mexico, 1846(Norman: University of Oklahoma Press, 2010), 235.
 Dishman, 142.
 Campbell, 144.