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  • James Houser

March 28, 1862 - The Confederate Invasion of New Mexico & Battle of Glorieta Pass

Updated: Jun 7, 2021

March 28, 1862. Two ragtag forces wearing Union blue and Confederate grey square off at a desolate, isolated mountain pass in northern New Mexico. The westernmost battle of the American Civil War – the “Gettysburg of the West” – begins. It marks the climax of one of the strangest and least-known campaigns of the whole war: a Confederate attempt to conquer New Mexico, Arizona, and eventually the whole West.

When the American Civil War began, most people were focused on Virginia, Kentucky, and Missouri: the main theater of war. This was, of course, where the action was and where the decisive events of the war would take place. Events farther west than Missouri were far from the minds of Abraham Lincoln and Jefferson Davis. Some Confederates, however, saw opportunity in the American Southwest. The people there had felt neglected for quite a while, and most inhabitants of the New Mexico Territory – modern day Arizona and New Mexico – were Southern immigrants opposed to Union control and welcoming of any Confederate attempt to stake a claim in the Southwest.

When Texas seceded from the Union in 1861, Confederate forces took possession of Fort Bliss, Texas on the Rio Grande River – the gateway to the New Mexico Territory. New Mexico was held by a small garrison of about 3000 Union soldiers, a mix of long-service regulars and local militia; all the good troops had been sent east to Virginia. They were under the command of Colonel E.R.S. Canby, a brilliant administrator and expert in Spanish but not much of a combat soldier. His small force was not enough to protect the long boundaries of the territory from Confederate incursions.

In July 1861, Confederate cavalry ran a raid into southern New Mexico and Arizona. Defeating a small militia force at Mesilla, Colonel John Baylor declared a Confederate Territory of Arizona, centered on Tucson and Mesilla – essentially staking a Confederate claim to this United States territory. Baylor reported back to the Confederate government that the Union was weak in the Southwest, and a decent effort there might win the war. If the Confederates could overrun New Mexico, they could move on to take California, Colorado, and even Oregon, cutting the Union off from the Pacific and opening a whole other front to the Civil War.

General Henry Hopkins Sibley, a Confederate general of dubious background and with truly unhealthy levels of alcohol consumption, presented a plan to Jefferson Davis to advance up the Rio Grande and take the major Union forts in the area: Fort Craig south of Santa Fe, and Fort Union all the way to the north. With an army of 2600 men, Sibley wanted to completely conquer New Mexico and establish a springboard for further operations. Davis approved, probably figuring “what the hell.” It was a small investment for a possibility of a large return.

In December 1861, Sibley arrived at Fort Bliss and took command of his ramshackle Army of New Mexico. Consisting mostly of undisciplined Texas cavalry, he started his advance up the west bank of the Rio Grande in February 1862. Sibley looked for an early confrontation with Canby’s main force of 3000 at Fort Craig, which stood across his path. Sibley knew that attacking the fort was a stupid idea, so he tried to maneuver around it, cut off its lines of supply, and draw the Union out of hiding.

Sibley’s gambit succeeded, and Canby came out to fight at Valverde on February 21, 1862. This was a tiny battle by Civil War standards farther east - neither force was larger than 3000 men, compared to First Bull Run the previous summer where each side had 30,000, or Gettysburg the next year where both sides would have from 70,000 to 90,000 men. Still, Valverde was a bitter, tough fight, and despite Sibley being drunk on the field and having to give up command to a junior, the Confederates prevailed. Canby retreated back into Fort Craig – but he didn’t surrender.

Now Sibley, despite having won the battle, was in trouble. He had very little food with his army – he had planned to pick up more food from Fort Craig once he had captured it, and ransack Union stores on the way. Even though the Union had lost the Battle of Valverde, by not losing the fort they had put Sibley in a major quandary. He had too little food to retreat or lay siege; the only thing to do was keep going north and try to take Union food stores at Santa Fe or Albuquerque.

Even worse, the Confederates had lost so many horses at Valverde that he could no longer move as fast as he wanted. He either saw no other option, or was too drunk to care. Probably a little bit of both. Leaving Canby and his force behind, Sibley kept moving north with his starving army. Canby was not idle. He immediately sent out small forces of cavalry to harass and ambush Sibley on his way north, and sent a message to Fort Union telling them Sibley was coming. Unless Sibley could fight his way out to the north, any retreat would have to pass by Fort Craig again; unless he won a battle, there was no escape. To the east and west lay only desert.

In the meantime, Canby’s cavalry removed all the supplies from Albuquerque and Santa Fe. When Sibley captured those cities on March 2 and March 13, he found no food, no ammunition and no escape. Worse, due to his slow movements Union volunteer units had arrived from Colorado to reinforce the bluecoats at Fort Union. The Colorado militia commander, Colonel John Slough, led out a mixed force of 1300 men to try and stop Sibley’s advance.

Sibley pushed forward the only portion of his army that was still mounted – 1100 men under Major Charles L. Pyron. They ran headlong into Slough’s Colorado infantry and Regular cavalry at Glorieta Pass on March 28, 1862. This battle, even smaller than Valverde, was nevertheless one of the most decisive, unsung battles of the war. Neither overall commander – Canby or Sibley – was there. It was solely a battle of junior officers commanding small squads and platoons of riflemen and cavalry, swirling around small complexes of adobe ranch buildings, cornering each other in canyons, and with a small number of cannon blazing away at fast-moving troops. It was an absurd combination of a Civil War battle and a Wild West gun show.

Even as the battle was raging, a small Union force of cavalry slipped around the Confederate flank and found the whole Confederate supply train, 80 wagons, several cannon, and 500 horses and mules. Major John Chivington, later an infamous perpetrator of Indian War massacres, led his small troop into the supply train, burning all the wagons and leading off the horses.

The Confederates, again, won the Battle of Glorieta Pass, driving off Slough’s tiny army in what one historian describes as a “desperation unequaled by any engagement of the war.” The battle became known as the “Gettysburg of the West,” which is more of a fun name than a meaningful one. This tempest in a teapot gained the Confederates nothing. They may have won the battle, but with the burning of their supplies they had absolutely lost the campaign. They could go no farther forward.

Sibley’s campaign was ruined. He had fought and won two battles but had failed to capture either Fort Craig or Fort Union, his troops had no food and no horses, and he was trapped between two Union forces. Canby, realizing how weak Sibley had become, ordered both for his army to march north from Fort Craig and for Slough to march south from Fort Union, aiming to catch Sibley in a vise. Worse, Sibley learned that a column of California troops was approaching overland from the west. He was about to be surrounded.

Sibley’s exhausted troops had to retreat back to Texas over nearly open desert, foraging all the way. The retreat dissolved into an ordeal, a pathetic trek back over the desolate mountains and open sands of New Mexico and Texas. Hundreds of men straggled, pillaged and burned their way through every town they found, turning the New Mexico population hostile and angry. At a last stand near Peralta on April 12, they held off Canby long enough for the rest to escape. This is the battle depicted in the film “The Good, The Bad, and the Ugly.”

Sibley’s ruined army straggled back into Texas by early July. Sibley was never put in charge of a major force again, being put in charge of supplies and rear area details, where he could find all the liquor he wanted. His troops – what was left of them after battle, starvation, and heatstroke – were sent east to fight the Union in Louisiana. Canby was promoted and in 1865 oversaw the final capture of Mobile, Alabama at the end of the war.

This strange little campaign, so tiny in terms of numbers and men involved, is an amazing case of “what could have been.” What *would* have happened if the Confederates had somehow managed to capture New Mexico and threaten California and Colorado? What would be the consequences of Confederate armies in Los Angeles, Denver, or Salt Lake City? This was all probably a pipe dream, of course – the Confederates barely had the supply capacity to feed, clothe and arm Lee’s army right in front of Richmond, let alone launch a major attack into the wild West. Still…stranger things have happened.

The Confederates never threatened New Mexico again. Maybe next time make sure your general’s supply wagon has more maps and food, and less whiskey.

Book Recommendation: Hard to find good books on the Confederate invasion of New Mexico! Take a look at Thomas Edrington’s The Battle of Glorieta Pass: A Gettysburg in the West, March 26-28, 1862 (Albuquerque: University of New Mexico Press, 1998).

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