Tank Spring Nature Preserve is a State Dedicated Nature Preserve that is part of Martin State Forest. It offers a lollipop trail of about three miles; DNR describes the trail as “moderately rugged”. The lollipop stem is a gravel forest road that climbs rather steeply from the parking area. When the road finally reaches a ridge line and flattens out, it turns right and passes by a small pond. The loop begins just beyond that. Turn left and leave the forest road for a more natural path through mature woods. You’ll cross several intermittent stream beds that occupy very scenic if shallow valleys, and in places see much higher ground off to your right.
As the trail approaches a set of railroad tracks, it curves sharply to the right and dips briefly in toward Tank Spring. The spring derives its name from the fact that it once served as a water source for a tank that passing steam locomotives used to fill their boilers. The spring itself will probably be obscured by a jumble of large rocks and a riot of vegetation and tree trunks, but you’re likely to see a healthy trickle emanating from underneath all that.
The path soon climbs out of the spring valley and turns generally south, returning toward the beginning of the loop. About the time you encounter another pond to your left, the path turns sharply right and joins with a ridgetop forest road and returns to the beginning of the loop.
Directions: Martin County. From US 50 X IN 650, go southeast 0.8 miles on IN 650 to its end, then left 0.3 miles on Deep Cut Lake Road, then right 0.6 miles on County Road 54 (likely unmarked) to a parking area on the left.
GPS: N 38 41.420 W 86 42.453