Dunbar Cave was a popular resort for many years before becoming a state park. Beginning in 1875, investors developed stays at Dunbar Cave and nearby Idaho Springs, drawing visitors with the perceived medicinal qualities of the spring waters and the cool air venting from the cave that kept the area in front of it cool even in summer. Over the next 60 years, cabins, a wooden dance floor at the cave mouth, an artificial lake, and a three-story hotel were built, though the hotel later burned, and the resort changed ownership several times in the late 19th century. In 1931, the Dunbar Cave and Idaho Springs Corporation bought the cave and surrounding land and added electric lights in the cave, a swimming pool and bathhouse, a concrete dance floor and bandstand at the cave mouth, and an enlarged artificial lake. Big bands played there, including Benny Goodman, Glenn Miller, Lena Horne, and Tommy Dorsey, and the on-site Idaho Springs Hotel accommodated 200 guests. The bathhouse from that operation now serves as the park visitor center, and the original gate-house stands in the pollinator garden. Country musician Roy Acuff purchased the site in 1948, seeing potential for both country and pop shows in a region where country music parks were an important Sunday business often featuring performers from the Grand Ole Opry. Over the July Fourth weekend in 1948, Owen Bradley and his orchestra played on July 3, Acuff headlined a show on the Fourth followed by fireworks, and Beasley Smith and his orchestra performed the next night. Bradley continued to play many Saturday nights there over the following years. Acuff made Dunbar his home base when not touring, played there on Tuesdays and Fridays, and broadcast the Friday show on WSM from 11:30 p.m. until midnight. He installed his siblings Juanita, Briscoe, and Claude “Spot” Acuff as site managers and added a large amphitheater on the east side of the lake for the new country shows as well as a golf course. Air conditioning reduced the appeal of the cave's cool air, and as other forms of entertainment became popular, the resort drained Acuff's resources. He sold it in November 1966. The property closed in 1971 and was often vandalized. On Nov. 2, 1973, the State of Tennessee bought the remainder of the property and operates it as a state park through the Department of Environment and Conservation to preserve and protect Dunbar Cave's cultural, natural, and historical resources.