Devils River State Natural Area is a 37,000-acre (15,000 ha) section of three ecosystems, the Edwards Plateau, the Tamaulipan mezquital and the Chihuahuan Desert. It is located 66 miles (106 km) north of Del Rio, Val Verde County in the U.S. state of Texas. In 1873, Texas Ranger Captain Pat Dolan had a skirmish with Native Americans, at the falls named for him. Dolan Falls in the natural area is the highest volume waterfall in Texas.