Claim: Eagle Cave is an onyx cave that was discovered in 1849, opened to the public in 1938 and offers over 3,000 feet of passages for exploring across eight levels in Richland County, Wisconsin, United States.
Evidence: Eagle Cave is an onyx cave located near Blue River, Wisconsin, in Richland County, Wisconsin, United States. The cave was discovered in 1849 and opened to the public in 1938.