Go here for the link: http://wesclark.com/jw/mormon_battalion.html
Officially the 1st Iowa Volunteers, President Polk requested volunteers from Mormon leader Brigham Young in 1846 at the onset of the Mexican War. The Mormons at that time were in Iowa Territory. Over 500 Mormon men travelled from Council Bluffs, Iowa, to Santa Fe, in what is now New Mexico. They eventually were under the command of Colonel Steven Kearney, who was in command of the Army of the West, and proceeded to California via San Diego and eventually to Los Angeles. After the war, some of the men settled in Arizona or California, with others moving the Utah.
Go here for the map: http://www.three-peaks.net/battalion.htm