On 10 and 11 January 1847, the Mormon Battalion crossed the Colorado River at this approximate site during its march to California. The battalion consisted of 500 volunteer soldiers from among the Mormon pioneers as they crossed Iowa in 1846, and they were mustered into the United States Army at Council Bluffs, Iowa, on 16 July of that year to serve in the War with Mexico. They marched down the Missouri River to Fort Leavenworth, where they joined the Army of the West under General Stephen W. Kearney, then proceeded to Santa Fe, New Mexico, which advance elements of the Army had already occupied. The Mormon soldiers, all members of the Church of Jesus Christ of Latter-day Saints, were then assigned the mission of carving out a wagon road from New Mexico to California so the U.S. Army could more easily supply its outpost in southern California and others planned for the Southwest. The Mormon Battalion completed its march in San Diego on 29 January 1847.