FEATURES: This loop hike passes by two old iron mines, one of which extends 100 feet into the hillside and can be entered. LENGTH: 3.0 miles. DIFFICULTY: Easy to moderate. TIME: About two and a half hours. STARTING POINT: Highlands Natural Pool entrance.

The hike begins at the Highlands Natural Pool entrance, on light-green blazed the Otter Hole Trail. You’ll be following this trail for the first part of the hike (other trails, such as the “L” Trail and the “W” Trail, are co-aligned for part of the way).

Starting at the Pool entrance, follow the Otter Hole Trail along the mine brook to your left. The trail briefly follows a dirt road, then bears left and ascends on a footpath, passing a waterfall and the weir that regulates the supply of water to the pool.

After crossing a footbridge over the brook, the green-blazed Otter Hole Trail proceeds through a rocky area, bears left, and reaches a wide woods road – the continuation of Snake Den Road. Here, the Otter Hole Trail turns right and follows the road, but you should cross the road and continue ahead on the joint Mine (yellow-on-white) and Hewitt-Butler (blue) Trails. The joint trails ascend on a footpath through mountain laurel and then climb more steeply through a rocky area.

The joint trails level off and reach a junction where the trails split. The blue-blazed Hewitt-Butler Trail continues ahead, but you should turn left and follow the yellow-on-white blazes of the Mine Trail. The trail passes some interesting jumbled boulders and rock outcrops on the left and begins a steady descent. After a while, the descent moderates, and the trail joins an old woods road.

After passing through a somewhat open area, where many of the trees have died due to a combination of drought and gypsy moth infestation, you’ll reach a T-intersection, where the red-blazed Wyanokie Circular Trail comes in from the right. You should turn left and follow the joint Mine and Wyanokie Circular Trails, which descend slightly to cross an intermittent stream.

A short distance ahead, you’ll see on the left the ruins of a stone shelter, constructed by members of the Green Mountain Club in the 1930s. The trail now approaches Blue Mine Brook. Just before reaching the brook, you’ll notice a circular mine pit to the right of the trail, with a small pile of tailings (discarded waste rock) to its left. The trail crosses the brook on a wooden footbridge, built as an Eagle Scout project in 2002.

Turn right after crossing the footbridge and proceed ahead for about 100 feet. To the left is the Blue Mine, filled with muddy water. This mine, named for the dark blue color of its ore, was discovered by Peter Hasenclever about 1765 and was worked extensively in the 1800s. A large concrete pad at the entrance to the mine, with protruding iron rods, once served as a base for steam-operated equipment.

Go back to the footbridge (do not recross it) and continue ahead on the joint Mine/Wyanokie Circular/Highlands Trails. Almost immediately, the Highlands Trail leaves to the right, but you should continue ahead on a rocky woods road, following yellow-on-white and red-on-white blazes. Bear left at a fork and continue ahead for about a quarter of a mile until the two trails separate. Here, you should turn right and follow the yellow-on-white blazes of the Mine Trail, which climbs on a narrow woods road, once used to access the Roomy Mine. At the top of a rather steep pitch, the Mine Trail turns sharply right, but you should continue ahead on the old road, now following the orange blazes of the Roomy Mine Trail.

At the top of the rise, the entrance to the Roomy Mine is on the right. Named for Benjamin Roome, a local land surveyor, the mine was opened shortly after 1840 and worked until 1857. To enter the mine, you first have to crawl through a short passage that is only about two feet high. That leads to a large chamber, with the horizontal shaft heading into the mine directly ahead. The shaft is about six feet high and leads 60 feet into the hillside, where it dead-ends. The temperature inside the mine is a constant 52 degrees, and the floor is usually wet.

Continue to follow the orange blazes of the Roomy Mine Trail along the mine road. Soon, the trail bears right onto another road (the red-on-white-blazed Wyanokie Circular Trail ends here). A short distance ahead, at a huge boulder, turn left (as indicated by the signs for "Weis" and "Falls") and continue to follow the Roomy Mine Trail, which climbs over a rise and passes interesting rock outcrops.

After a jog to the right, the trail crosses Blue Mine Brook above a waterfall, briefly follows the brook, then turns left and continues to a junction with the yellow-on-white-blazed Mine Trail. Here, the Roomy Mine Trail ends, and you should turn right onto the Mine Trail. (From here to the end of the hike, you'll be retracing your steps.) The trail is level at first, then climbs steadily.

At the top of the climb, turn right, joining the blue-blazed Hewitt-Butler Trail. Now following both blue and yellow-on-white blazes, descend steeply to Snake Den Road, here a dirt road. The Hewitt-Butler and Mine Trails end here, but you should cross the road and continue ahead on the green-blazed Otter Hole Trail back to the Highlands Natural Pool.

View More Hikes.

Their office is at 156 Ramapo Valley Road, Mahwah. Phone: (201) 512-9348, Website: nynjtc.org.