Devil's Sinkhole State Natural Area

The ground simply opens. A shaft about 50 feet wide drops 140 feet into a cavern more than 320 feet across and 350 feet deep, parts of it below the water table, where small lakes ring the floor and hold a native amphipod and a rare aquatic isopod. A Mexican fern found in only a few places in the United States grows on the walls of the shaft. Native people knew the sinkhole long before settlers, camping here seasonally to hunt, gather plants and collect chert for tools. Local lore credits Ammon Billings with naming it after his first look in 1867. It became a National Natural Landmark in 1971.

The land was part of the Whitworth Ranch. Clarence Whitworth raised Angora goats and, as a county commissioner, helped bring utilities and medical care to Rocksprings; Katherine Nicholson Whitworth taught high school English and painted. The state bought the first tract from the family in 1985 and opened it for bat tours in 1992, and a 2026 addition brought it past 3,000 acres.

From late spring to early fall, Mexican free-tailed bats roost in the cavern, one of the largest colonies in Texas, and on warm evenings up to three million rise out of the shaft to hunt, eating as much as 30 tons of beetles and moths a night. No one enters the cavern. Every visit is a guided tour run by the Devil's Sinkhole Society, starting at the visitor center on the square in Rocksprings and ending at a wheelchair-accessible platform over the shaft.