Osio Rock is the southernmost hill accessed by a trail in Norvin Green State Forest. It's bare rock top has panoramic views of the NJ Highlands and the New York metro area. Less than a mile from the trailhead at Otter Hole, it feels like a nice eastern mountain on a miniature scale. The view of the New York skyline from the top is one of the best in the NJ Highlands.
Norvin Green State Forest is home to some of the best hiking in New Jersey. Located on the Wyanoke Plateu, it is full of steep, rocky ridges and hills, some pristine streams and the beautiful Chikahoki Falls. A dense network of trails created and maintained by the New York-New Jersey Trail Confrence runs through the southern half. The forest also has the advantage of being more accessible than other hiking destinations in New Jersey; it is much closer to the New York suburbs than Abram S Hewitt State Forest or Wawayanda State Park or especially Stokes State Forest. Thought the Osio Rock hike starts from a different trailhead, the primary entrance is through the Weis Ecology center (see link below).
The trailhead is located at the Otter Hole (an interesting water feature) on Glenwild Avenue, outside of Butler. Getting there can be confusing. From Route 23 east, take a right onto CR 511 north, and go through Butler. After a bridge over the Pequannock River, turn left and then right shortly after onto Glenwild Avenue. After about 2 1/2 miles, pass Lake Kampfe on the left and a pullout for the yellow blazed Wyanoke Crest trail on the right. This is NOT the trailhead. Another mile later, at the road's highpoint, the parking lot for the trailhead for is on the right. Take the blue blazed Hewitt Butler trail, which crosses the road.
Follow it south (the opposite side of the road from the parking lot). The trail turns right, and soon there is a junction with the red blazed Torne trail. Take either trail; they meet back up again in less than a half mile. The Torne trail goes through mostly flat woods, while the Hewitt Butler trail climbs Torne Mountain. On Torne Mountain, there are two main viewpoints. The first has a firepit and some stone benches and looks to the west. The second looks to the south. The two trails meet back up again near a ravine with a small spring in it, and the Hewitt Butler trail continues, climbing up to Osio Rock. The summit is obvious - mostly bare rock. Return the same way.
Osio Rock is named "Torne Mountain" and Torne Mountain is unnamed on the USGS map of the area. But on the New York-New Jersey Trail Conference map and on the map of Norvin Green State forest that is given out at the Weis Ecology Center, the names are correct.
Like all hiking spots in this part of New Jersey, Osio Rock is very close to private property and suburban backyards. Anyone hiking off the trail should be careful of the park boundaries.
External LinksNorvin Green State Forest website
Weis Ecology Center