The nearly 39,000-acre Chinati Mountains State Natural Area lies south of Pinto Canyon Road and just west of the high peaks of the Chinati range. The mountains formed in the largest volcanic eruption in the Trans-Pecos region, more than 35 million years ago, and the rugged peaks and steep canyons tell the story. The area has a 4,400-foot elevation change. The natural area is not yet open to the public.