For many centuries, Hoosier Pass linked the Utes’ important hunting grounds in South Park and Middle Park at the heart of their mountain domain. By the 1400s or 1500s, these hunter-gatherers occupied territory from Utah’s desert to the Front Range of present-day Colorado. After Spaniards introduced the horse in the 1600s, the Utes’ riding skill and superior topographical knowledge made them powerful warriors, and they routinely defeated other tribes that challenged their control of South Park. Early non-Indian visitors generally passed without conflict, but permanent settlers were unwelcome. In the late nineteenth century, however, increasing pioneer settlement forced the Utes from their mountain strongholds, and by the 1880s they had been confined to reservations in Colorado and Utah. On June 23, 1844, returning from California on the second of his five western expeditions, John C. Frémont crossed Hoosier Pass after detouring into Colorado to locate the sources of the Platte, Grand, now Colorado, and Arkansas rivers. He mapped the surrounding region with the help of guides including Kit Carson and cartographer Charles Preuss, and his widely read journals, ghostwritten by his wife Jessie and promoted by his father-in-law, Sen. Thomas Hart Benton of Missouri, helped stir the nation’s imagination and encourage migration west.