In 1846, Mormons camped mainly on the shores of the Missouri River were already exiled from the United States and bound for a refuge in the west when a call to arms came from the U.S. government to serve in the Mexican War. President James K. Polk needed 500 enlisters, and the call was politely received but with suspicion and resentment because of earlier rebuffs when redress was sought for persecution in Missouri. Brigham Young saw an opportunity to demonstrate loyalty to the United States and secure monies from the government. On July 15, gathering at present day Council Bluffs, Iowa, 513 soldiers left with 33 women and 42 children for Fort Leavenworth, Kansas. On August 12, after being outfitted, they continued a 2,030-mile march to the California coast and, despite intense suffering from lack of adequate food, water and raiment, constructed the first wagon road from Sante Fe to the Pacific Ocean and opened the entire southwest for settlement. After enduring their march for over six months, they reached mission San Diego on January 29, 1847.