Split Rock, or Twin Peaks, is a mountain in central Wyoming’s Granite Mountains near the Sweetwater River Valley, a major natural passage through the Rockies. Its distinctive V-shaped cleft made it an easily recognized landmark along a broad corridor with water and grass that supported travel across difficult country. Trails here were used first by High Plains Indigenous peoples following game, then by Astorians under Robert Stuart in the early nineteenth century, with parts of that route later joining the Oregon, California, and Mormon Pioneer trails. From about 1812 to 1912, many kinds of westbound travelers passed by Split Rock, which remains significant as both a geologic feature and an overland travel landmark.