Orange Spring in Marion County

Orange Spring is a third-magnitude spring with a kidney-shaped pool that measures 110 feet long by 90 feet wide, bordered by a low concrete wall. The spring issues from a deep, circular depression about 25 feet in diameter in the south-central part of the pool. Previously, divers have entered the vent to access the cavern below. The cavern is entirely within the Hawthorn Group, floored by sand, silts, and clays. Water enters the cavern from a vent to the side of the cavern. The water in the spring pool is a murky green with a hydrogen sulfide odor, with algae and aquatic vegetation on the pool bottom. Discharge is toward the northeast over a man-made, limestone waterfall. The spring run flows about 500 feet to Orange Creek.