Green's Bluff in Owen County is all about wild geology and clear water. Boone's Cave is an aquatic cave system and one of the longest caves in Indiana. A spring fed stream pours from an opening at the base of the bluff. Rare eastern hemlocks grow on cool north facing slopes. Sandstone walls rise above a bend in Raccoon Creek. Along the water you can spot remnants of an 1840s grist mill. Expect a great blue heron rookery, owls, salamanders, and the occasional bobcat track.

Two moderate loop trails wind through steep bluff country and stay beautifully quiet. The Nature Conservancy protects more than 1,100 acres with free access. About 15 minutes south of Spencer and roughly 30 minutes from Bloomington. Wear real hiking shoes for roots and rock. Boone's Cave sits about a mile off the main loop along a creek path, so a printed map helps in the valley. Admire the cave from outside to protect the bats that live inside. Time it for spring wildflowers, fall color, or clear winter views.