The Mormon Battalion was the only religious unit in United States military history in federal service, recruited solely from one religious body and having a religious title as the unit designation. The volunteers served from July 1846 to July 1847 during the Mexican–American War of 1846–1848. The battalion was a volunteer unit of between 534 and 559 Latter-day Saint men, led by Mormon company officers commanded by regular U.S. Army officers. During its service, the battalion made a grueling march of nearly 2,100 miles from Council Bluffs, Iowa, to San Diego, California.