North American Horse Encyclopedia

he earliest reference to horses being in the southwestern Utah area is from the journal made by Father Silvestre Velez de Escalante during the 1776 Dominguez-Escalante expedition.

The Sulphur Herd Management area horses that are present as adopted horses in the Salt Lake City area appear to be of Spanish phenotype. The horses were reasonably uniform in phenotype, and most of the variation encountered could be explained by a Spanish origin of the population. That, coupled with the remoteness of the range and blood typing studies, suggests that these horses are indeed Spanish. As such they are an unique genetic resource, and should be managed to perpetuate this uniqueness. A variety of colors occurs in the herds, which needs to be maintained. Initial culling in favor of Spanish phenotype should be accomplished, and a long term plan for population numbers and culling strategies should be formulated. This is one population that should be kept free of introductions from other herd management areas, as it is Spanish in type and therefore more unique than horses of most other BLM management areas.

How exactly the Sulphur horses came to Mountain Home will probably never be known. It seems unlikely that they were escapees from any Jedediah Smith's expeditions since, although he was once within sight of mountain, his narratives do not indicate he lost any horses in the region. The Dominguez/Escalante expedition didn't come any closer to Mountain Home than Frisco, which is about 30 miles away. The Padres then traveled to within 25 miles of the southern end of Needle Range, to a site marked by the "Casting of the Lots" Monument. The Spanish Trail passed a somewhat less distance, north of the fore-mentioned Newcastle, from the Needle Range than did the Padres' route, just further south and west. It's unlikely that any parties moving goods along the trail would have deviated far enough from the route to lose or abandon livestock at Mountain Home. It's more likely that the horses were escapees from caravans that lost horses in the Escalante Valley near the southern end of the Needle Range, from which point the horses migrated northwestward. Or, they may have been brought there by Indians or Mormon settlers who either released them⁸, or from whom they escaped into the rugged terrain. It does seem that the herd descends from a relatively few individuals, given the uniformity of the mtDNA and blood markers⁹ amongst them.