From the sign for Castle Arch, drive up Horse Canyon 0.2 mile to "Fortress Arch sign" on the right. A 1/2 mile trail goes to the arch viewpoint on a side canyon. The arch is accessible via a long bypass on a side canyon behind the arch location which require abilities on route finding. The Arch has a span of 115 feet (35 meters). This arch is located and named on the 7.5 topo map "South Six-Shooter peak" Utah.