After war was declared in May 1846 between the United States of America and the Republic of Mexico, the initial American military strategy was to dispatch three separate field armies, parts of U.S. Army units and defeat the Mexican armed forces inside Mexican territory. Several months into the conflict, the U.S. military leadership recognized that a fourth army would be needed to bring the war to an end. This army, under General Winfield Scott, was to mount a direct assault on the Mexican capital city via an amphibious landing near Vera Cruz and then due west to Mexico City proper.
- The Army of Occupation – General Zachary Taylor (Old Rough-and-Ready and later 12th U.S. President) was given orders to position his army at the banks of the Rio Grande River in south Texas at Point Isabel (now Corpus Christi), opposite the Mexican town of Matamoros. His objective was to take control of coastal northeast Mexico, including Monterey.
- The Army of the Center – Brig. General John E. Wool was assigned to assemble an army of state volunteer militias at the Texas town of San Antonio with orders to march and secure the key towns of Chihuahua and Parras in north central Mexico.
- The Army of the West – Colonel Stephen Watts Kearny was charged with assembling an army at the headquarters of the 1st Regiment of Dragoons at Fort Leavenworth, Kansas with two objectives: 1) Capture Santa Fe, the territorial capital of Nueves (New) Mexico, and 2) Proceed west across the mountainous and desert terrain of the Southwest to the coastal port town of San Diego in Alta (Upper) California. Here Kearny was to connect with U.S. Navy and Marine forces of the Pacific Squadron under Commodore John Sloat, who was later replaced by Robert F. Stockton. The Navy and Marines were to secure the major coastal port cities of Yerba Buena (San Francisco), Monterey, San Pedro (Los Angeles) and San Diego. Kearny’s Army of the West would provide the required manpower to occupy and establish a U.S. government and security force to Alta California.
To assemble his Army of the West, Kearny was authorized to solicit volunteer state militias from Missouri and a 500-man infantry battalion from the Mormon immigrants spread out in Iowa Territory. He ordered Dragoon Companies C and K serving in outposts in Michigan and Wisconsin to assemble at Ft. Leavenworth. The advance elements of Kearny’s Army of the West that left Fort Leavenworth in June 1846 consisted of:
- 300 regular army dragoons: Co. B, C, G, I and K
- 100 volunteer infantry (a 2 company battalion) from Missouri
- 100 St. Louis cavalrymen (LaClede Rangers)
- 50 Shawnee and Delaware Indians as scouts
- 850 1st Regiment of Missouri Mounted Volunteers under Col. Alexander Doniphan
- 150 Missouri Volunteer Artillery Battalion (St. Louis) under Major Meriwether Lewis Clark hauling twelve 6-pounder cannons and four 12-pounder mountain howitzers.
Accompanying this assemblage were:
- 1556 wagons (baggage and supplies)
- 459 horses
- 3658 draft mules
- 14,904 cattle and oxen
Thus this Army was not just a bunch of soldiers jumping on their horses and riding through the open gates of a fort on a patrol. Rather, this column truly represented a massive logistical undertaking of orchestrating a huge assemblage of men, supplies, wagons, and livestock. An incredible amount of sophisticated organization was required to lead and feed the troops, teamsters to drive the supply wagons, and personnel to herd and feed the livestock. It took Kearny’s Army an entire month just to travel the some 536 miles to the resupply depot at Bent’s Fort on the Arkansas River.
Following Kearny’s initial departure, two additional attachments to the Army of the West arrived at Ft. Leavenworth in August 1946: 1) The ~500-man 2nd Regiment of Missouri Mounted Volunteers under Col. Sterling Price, a leader of mob violence against the Mormon settlers in Missouri, and 2) the 496 infantry men and some 80 dependent women and children of the Mormon Battalion under Lt. Col. James Allen (regular Army dragoon captain).
Rather than a single cohesive unit, the Army of the West was a composite of six basic units to cover assigned objectives and orders.
- Kearny and his 1st Dragoons were the vanguard group of 300 regular mounted dragoons. After having the peaceful securing of Santa Fe, Kearny proceeded west to California. At Sorocco, New Mexico Kearny was met by Kit Carson and a group of about 20 mountain men from John C. Frémont’s California Battalion who were on their way to Washington, D.C. with dispatches from Commodore Stockton that California had fallen to combined U.S. Navy and Marine forces and Frémont’s 234-man California Battalion. Based on this information, Kearny retained Carson as a guide to California and sent (in retrospect, inadvisably) 200 dragoons and all his supply wagons back to Santa Fe. Kearny proceeded on to California post haste with 100 dragoons from Co. C and K, Lt. William Emory’s topographical engineer group, pack mules laden with supplies in place of cumbersome wagons and two 12-pounder mountain howitzers in tow. At this time Kearny hand selected dragoon Captain Philip St. George Cooke of Co. C to return to Santa Fe, take command of the Mormon Battalion when they arrived in Santa Fe and with them make a wagon road to San Diego.
- Col. Doniphan and his 1st Regiment of Missouri Mounted Volunteers left from Santa Fe with orders to travel due south on the Santa Fe Trail to Chihuahua and re-enforce Gen. Wool and his Army of the Center. Doniphan’s command had been engaged in protecting New Mexican ranchos and settlements from marauding Apache, Navajo and Comanche looting parties.
- Col. Price and the 2nd Regiment of Missouri Mounted Volunteers were assigned command of Santa Fe at Fort Marcy. They replaced Col. Doniphan as the army garrison post commander to continue in providing law and security to the New Mexico area under American constitutional law as established by Gen. Kearny. Col. Price also engaged in several armed conflicts to put down local revolts to American occupation of New Mexico, most notably at the mountain town of Taos.
- The Mormon Battalion was to provide Gen. Kearny with the needed manpower to occupy San Diego and Los Angeles. Upon leaving Santa Fe under Lt. Col. Cooke, the Battalion’s objective was to create a wagon road across the Southwest desert and mountains to San Diego. In San Diego and Los Angeles, the Mormon Battalion provided Kearny with troops to fulfill his orders as the military governor of California and to establish law and order to the area during the transition to a U.S. constitutional form of government. On May 31, 1847, a selected group of 15 Mormon Battalion men accompanied a 64-man detail escorting Gen. Kearny from Monterey back to Ft. Leavenworth with Lt. Col. John Frémont under arrest to be court-martialed in Washington, D.C. Among the escort were Capt. Cooke (returned to his previous dragoon rank after relinquishing command of the Battalion) and Dr. Sanderson.
- Col. Jonathan Stephenson commanded 500 1st New York Volunteers (originally the 7th New York Volunteers) who sailed from New York around Cape Horn and landed at Monterey, California in March 1847. They took over garrison and security duty in California upon Kearny’s departure to the East. The reenlisted 82-man Mormon Volunteers served in San Diego under Col. Stephenson’s command until March 1848 after the Mormon Battalion was discharged in Los Angeles on July 17, 1847.
- A battery of 3rd U.S. Artillery of about 100 soldiers with Lt. William T. Sherman (later a Civil War Union General) also arrived with the New York Volunteers.
The Army of the West was an integral part of the U.S. military strategy to secure and occupy key territorial assets in the West deemed essential to President James K. Polk’s plan of “Manifest Destiny” to expand the United States from the Atlantic to the Pacific Ocean. The Mormon Battalion played an essential role as an element of Kearny’s Army of the West in providing Gen. Kearny with the needed manpower to establish his role as military governor of California and in helping maintain peace and the American form of government and law to the citizenry of southern California. As part of their military assignment the Battalion established a vital southern trail wagon road across the Southwest mountains and deserts to the Pacific coast. This route was used by future westward migration traffic and commercial enterprises, such as rushers seeking the California gold fields, the Butterfield Stage Line and the Southern Pacific Railroad.
Bauer, Jack, The Mexican War, MacMillan Press, 1974
Hughes, John Taylor, Doniphan’s Expedition
Dawson, Joseph, Doniphan’s Epic March, Univ. of Kansas Press, 1999.
Urwin, Gregory J.W., US Cavalry: An Illustrated History 1776-1944
Eisenhower, John S. D., So Far from God: The US Mexican War 1846-1848, New York, 1990.