The Blue Hole is a freshwater pond and was a tourist site from the 1920s to 1990 and had 165,000 visitors annually.
Vintage postcard (c. 1936) depicting the entrance gate to the Blue Hole in Castalia, Ohio.
Vintage postcard (c. 1940) depicting the entrance to the Blue Hole in Castalia, Ohio.
Vintage white border linen postcard depicting visitors watching fish in the trout stream at the Blue Hole in Castalia, Ohio.
Vintage linen postcard (c. 1930s) picturing the Trout Hatchery and Water Wheel at the Blue Hole, Castalia, Ohio.
Vintage linen postcard depicting a scene at the Blue Hole in Castalia, Ohio.
Vintage linen postcard depicting a night scene at the Blue Hole in Castalia, Ohio.
Vintage linen postcard depicting the Mill Pond and Fish Hatchery at the Blue Hole in Castalia, Ohio.
Vintage linen postcard (c. 1930s) depicting a scene at the Blue Hole in Castalia, Ohio.
Vintage linen postcard depicting the famous Blue Hole in Castalia, Ohio.
Vintage linen postcard depicting the entrance to Blue Hole in Castalia, Ohio.
Vintage linen postcard depicting a scene at the Blue Hole in Castalia, Ohio.
Vintage linen postcard depicting the aerating water wheel at the Blue Hole in Castalia, Ohio.