Frémont followed the Santa Fe Trail, passing Bent's Fort before heading west and entering the San Luis Valley of Colorado in December. The party then followed the North Branch of the Old Spanish Trail, crossing the Continental Divide at Cochetopa Pass and continuing west into central Utah. But following the trail was made difficult by snow cover. On occasion, they were able to detect evidence of Captain John Gunnison's expedition, which had followed the North Branch just months before.