60 See below Guided tours are available for Twin Caves. This is a 20 minute boat tour and is available weekends April to Memorial Day and Labor Day to the end of October. Trips are daily from Memorial Day weekend to Labor Day. Reservations can be made each morning, in person, at the cave. Early arrival is recommended.
Hours vary according to season.
Donaldson Cave, dry side only, can be explored without a guide but proper caving gear is recommended. All other karst features within the park must must have a permit to be explored. Note that all caves are wet with flash flooding possible, and should not be entered during heavy rains. Caution should be exercised and experience is recommended. The 67-acre Donaldson Woods Nature Preserve is a rare stand of virgin hardwood forest similar to that which once blanketed most of Indiana.