The Sabinal River rises in fissure springs that flow from great slabs of limestone in the Lost Maples State Natural Area, seven miles north of Vanderpool in northwestern Bandera County (at 29°52' N, 99°36' W). It flows southeast to the Balcones Escarpment, where its course changes to the east and then to the west, and thence to its mouth on the Frio River, ten miles south of Sabinal (at 29°06' N, 99°27' W). The river is sixty miles long. In several places it sinks underground to rise again downstream. The sparkling stream is fed by Hale, Hollow, and Can creeks within the park and by Mill, Little, and Onion creeks south of the park. Cañon Creek, in Uvalde County, is called the West Prong of the Sabinal. The river traverses flat to rolling terrain with fractures, faults, and folds, surfaced by sandy and clay loam that supports hardwoods and grasses. Along the course of the Sabinal was a well-known Indian trail marked on early Spanish maps as Comanche Trail. The river was originally called Arroyo de la Soledad, Spanish for "Stream of Solitude." Most of the Sabinal River flows through the Edwards Underground Water District.