Mormon Battalion The Mormon Battalion was the only religiously based unit in United States military history , and it served from July 1846 to July 1847 during the Mexican - American War . The battalion was a volunteer unit of between 534 and 559 Latter - day Saints men led by Mormon company officers , commanded by regular US army officers . During its service , the battalion made a grueling march nearly 2 , 000 miles long from Council Bluffs , Iowa , to San Diego . The battalion ' s march and service was instrumental in helping the US secure much of the American Southwest , including new lands in several Western states , especially the Gadsden Purchase of 1853 of much of southern Arizona . The march also opened a southern wagon route to California . Veterans of the battalion played significant roles in America ' s westward expansion in California , Utah , Arizona and other parts of the West . Enlistment . At the time they enlisted , members of The Church of Jesus Christ of Latter - day Saints were seeking U . S . government aid for their migration west to the Rocky Mountains and Salt Lake Valley , despite having their previous petitions for redress of grievances denied . Under continued religious persecution , they had fled Nauvoo , Illinois , on 4 February 1846 across the Mississippi River . They camped among the Potawatomi Indians near what became Omaha , Nebraska . Brigham Young , the President of the Quorum of the Twelve Apostles , sent Elder Jesse C . Little to Washington , D . C . , to seek assistance from the federal government for the Mormon Pioneers fleeing for their lives from the mobs of Illinois . Little arrived in Washington D . C . on 21 May 1846 , only eight days after Congress had declared war on Mexico . Pennsylvania Army officer and attorney Thomas L . Kane offered the Mormons his advice and assistance . Politically well connected through his jurist father , Kane provided letters of recommendation and joined Little in Washington , D . C . The two called on the secretary of state , secretary of war , and President James K . Polk . After several interviews in early June 1846 , President Polk agreed to Little ' s offer if " a few hundred " men enlisted . On 2 June 1846 , President Polk wrote in his diary : " Col . [ Stephen W . ] Kearny was . . . authorized to receive into service as volunteers a few hundred of the Mormons who are now on their way to California , with a view to conciliate them , attach them to our country , and prevent them from taking part against us . " On 1 July 1846 Captain James Allen , dispatched by Colonel ( later Brigadier General ) Stephen W . Kearny , arrived at the Mormons ' Mosquito Creek camp . He had a request from President Polk to enlist a battalion of 500 volunteers to fight in the Mexican War . Most members of the Church were suspicious of the request , as the Federal government had ignored the persecutions they suffered . They were concerned about facing discrimination by the government , as they had from both the state and federal government in the past . Kane obtained U . S . government permission for the refugee Mormons to occupy Pottawattamie and Omaha Indian lands along the Missouri River . After carrying dispatches relating to the land agreements and battalion criteria to Fort Leavenworth , Kane sought out Little in the Latter - day Saint encampments on the Missouri . On 17 July 1846 , he held a meeting with LDS leaders and Captain Allen . Brigham Young had planned on moving the Mormons west that summer , but circumstances were against his plan . He saw several possible advantages to the Saints in the proposed federal service . Their enlistment would be a public relations victory for the church , demonstrating additional evidence of its loyalty to the United States . As the men were given a uniform allowance at Fort Leavenworth , Kan . , of US $ 42 each , paid in advance , for their one - year enlistment and as they were allowed to wear their civilian clothing for the march , the bulk of those funds were immediately donated to a general Church fund . These funds were used to purchase wagons , teams , and other necessities for the American exodus ( Actual wages paid over the next year to the Mormon Battalion totaled nearly $ 30 , 000 ) . Having been forced to leave farms and homes in Nauvoo , under threat , the Latter - day Saints were going to spend the winter on the banks of the Missouri River . Raising a group of able - bodied men would be difficult . Many men had already scattered to outlying areas where they sought jobs with wages to help support the group . Young wrote a letter to the Saints living in Garden Grove , in which he justified the call - up and asked for their help : The public approval of Brigham Young and other members of the Twelve were critical to gain men ' s enlistment . While some men quickly volunteered , Young had to persuade and cajole many enlistees . It took three weeks to raise the five companies of men . Allen ' s instructions were to recruit five companies of men who were to receive the " pay , rations , and other allowances given to other infantry volunteers . " Each company was authorized four women as laundresses , " receiving rations and other allowances given to the laundresses of our army . " Approximately thirty - three women , twenty of whom served as laundresses , and fifty - one children accompanied the men . Four women would eventually complete the cross - continental trek . The Mormon Battalion was mustered into volunteer service on 16 July 1846 as part of the Army of the West under General Kearny , a tough and seasoned veteran . His units included two regiments of Missouri volunteers , a regiment of New York volunteers who traveled by ships to California to meet him there , artillery and infantry battalions , Kearny ' s own 1st US Dragoons , and the battalion of Mormons . For years afterward , some Mormons viewed the Mormon Battalion as an unjust imposition and as an act of persecution by the United States . Journey begins . The battalion arrived at Fort Leavenworth on 1 August . For the next two weeks , they drew their pay , received their equipment ( Model 1816 smoothbore flintlock musket s and a few Harper ' s Ferry Model 1803 Rifle s ) , and were more formally organized into a combat battalion . The volunteers took the army ' s uniform allowance in cash . To be sure the Saints benefited from the men ' s wages , Young sent Orson Pratt to make sure the men handed over their first pay . Young used this and the wages they earned later to buy wagon loads of supplies for the main group at wholesale prices in St . Louis , Missouri . He wrote to the enlistees , that the money was a " peculiar manifestation of the kind providence of our Heavenly Father at this time . " There was little time for training and instilling discipline . Newly promoted Lieutenant Colonel James Allen became ill but ordered the battalion forward along the Santa Fe Trail to overtake Kearny ' s Army of the West . On 23 August , Allen died and was the first officer buried in what became Fort Leavenworth National Military Cemetery . Captain Jefferson Hunt , commanding A Company , was the acting commander until word reached Council Grove , Kansas , that Allen had died . A few days later Lieutenant Andrew Jackson Smith , West Point Class of 1838 , arrived and assumed temporary command of the battalion with the Mormons ' consent . For the next several weeks , the Mormon soldiers came to hate " AJ " Smith and the assistant surgeon , Dr . George B . Sanderson , for their treatment of the men , and the long marches suffered across the dry plains of Kansas and New Mexico . The Mormon men were not accustomed to the austere military standards of the day nor to the medical treatments imposed by Dr . Sanderson , including the use of feeding the sick mercury , which were standard for the time . Because the elders had counseled the battalion members to avoid military medical treatment by the military , they challenged the doctor ' s authority and unrest arose among the men . Smith and Sanderson continued to hold the Mormon Battalion to ordinary standards of discipline , and tensions continued . Cooke assumes command . Arriving in Santa Fe in October , General Kearny had dispatched Captain , now Lieutenant Colonel , Philip St . George Cooke , West Point class of 1827 , to assume command of the battalion . His assignment was to march them to California and to build a wagon road along the way . In Santa Fe all the women and children , except for a very few , and many sick men were sent to Pueblo , in present - day Colorado . A total of three separate detachments left the battalion and went to Pueblo to winter . For the next four months and 1 , 100 miles , Cooke led the battalion across some of the most arduous terrain in North America . Most of the Mormon soldiers soon learned to respect and follow him . The group acquired another guide in New Mexico – adventurer and mountain man Jean Baptiste Charbonneau , who as an infant had traveled with his mother Sacagawea across the continent with the Lewis and Clark Expedition . Lieutenant Smith and Dr . Sanderson continued with the battalion , along with Lieutenant George Stoneman , newly graduated from West Point that Spring . During the Civil War , all three officers were promoted to high - level commands for the Union Army . Afterward , Stoneman would go on to be elected Governor of California . Battle of the Bulls . Near the San Pedro River in Arizona lived a sizable number of wild cattle . The battalion reached this area in November , 1846 and their presence aroused curiosity among these animals . After the bulls of these herds caused destruction to some of the mules and wagons and resulted in two men being wounded , the men loaded their guns and attacked the charging bulls , killing 10 – 15 of the wild cattle , which was sarcastically termed the " Battle of the Bulls " . Capture of Tucson . Approaching Tucson , in future Arizona , the battalion nearly had a battle with a small detachment of provisional Mexican soldiers on 16 December 1846 . The Mexicans retreated as the US battalion approached . The local O ' odham and other Piman tribes along the march route were helpful and charitable to the American soldiers . Mormon soldiers learned many methods of irrigation from these native inhabitants and employed the methods later as pioneers in Utah and other areas . Temecula Massacre . Nearing the end of their journey , the battalion passed through Temecula , California , during the aftermath of the Temecula Massacre , a conflict between the Californio s and the Luiseño tribe . The Mormons stood guard to prevent further bloodshed while the Luiseño people gathered their numerous dead into a common grave . Journey complete . The Mormon Battalion arrived in San Diego on 29 January 1847 after a march of some 1 , 900 miles from Iowa . For the next five months until their discharge on 16 July 1847 in Los Angeles , the battalion trained and also performed occupation duties in several locations in southern California . The most significant service the battalion provided in California and during the war , was as a reliable unit under Cooke that General Kearny could rely on to block Fremont ' s mutinous bid to control California . The construction of Fort Moore was one measure Cooke employed to protect legitimate military and civil control under Kearny . Some 22 Mormon men died from disease or other natural causes during their service . About 80 of the men re - enlisted for another six months of service . A few of the men escorted John C . Fremont back east for his court - martial . A few discharged veterans worked in the Sacramento area for James W . Marshall at Sutter ' s Mill . Henry Bigler recorded the actual date , 24 January 1848 , in his diary ( now on display at the Huntington Library in San Marino , CA ) when gold was discovered . This gold find started the California Gold Rush the next year . $ 17 , 000 in gold was contributed to the economy of the Latter - day Saints ' new home by members of the Mormon Battalion returning from California . Historic sites and monuments . Historic sites associated with the battalion include : Monuments relating to the battalion are also located in New Mexico , Arizona , and Colorado , and trail markers have been placed on segments of the battalion route between Mt . Pisgah ( Iowa ) and San Diego .