Originally established as the Golden Eagle Winery in the mid-1800s, the Lonz family took it over in the 1920s. Over the years, this Bavarian castle-like structure built in 1942 has been visited by five U.S. presidents and a number of celebrities. In 2001, the state of Ohio acquired the land and established Middle Bass Island State Park. Enologist Claudio Salvador continues to make Lonz wines, a tradition he started in 1979.

Ohio Division of Natural Resources unveiled a restoration and preservation effort at the historic site in 2017, where the 150+ year old wine cellars were opened for the first time to park visitors. ODNR saved as much as the original structure as possible, including the cellars, the iconic Lonz Winery facade, and the tower. Historical wine exhibits are inside the preserved cellars of Lonz Winery. These exhibits feature wine-making equipment found on the property, some as much as a century old.