Hunterdon County, NJ | Department of Planning, Economic Development and Land Use | Union Furnance Section















Phone: 908-782-1158 * Fax: 908-806-4057

Virtual Tour

Arches section - Guide and Trail Map
Old Remains of Union Furnace


This 170-acre wooded preserve bordering Spruce Run Reservoir is named for the colonial ironworks that flourished here from 1742 to 1781. Established by William Allen and Joseph Turner for the production of horseshoes, farm implements, and chimney firebacks, the ironworks could produce 500 to 1,000 tons of iron a year. In order to melt the impurities in the iron at 3,000 degrees, slaves and immigrants cut down an acre of forest each day to fuel the furnace. During the Revolutionary War, the ironworks’ superintendent, Robert Taylor, cast military hardware such as cannonballs and rifle barrels. Allen and Turner were British loyalists and fled the area. When the forests were depleted of fuel, the furnace ceased operation. Taylor resumed operations at another foundry in High Bridge until his death in 1821. This facility, considered the oldest in the country, became known as the Taylor-Wharton Iron & Steel Company in 1912. In 1811, the Union Furnace site was sold to Hugh Exton, who built a three story gristmill called “Union Mill.” The County acquired most of the property in 1980, and purchased additional acreage in 2017. Today, this hilly terrain includes young and mature forest, a stretch of the Spruce Run, and the standing chimney of a slaves’ quarters.


A single hiking trail runs through Union Furnace. The trailhead is located across from the Spruce Run Parking Area. Part of the trail follows a historic mill race which used to supply water to the nearby Union Mill. Then it climbs up the hill and emerges onto Serpentine Drive. The trail is part of the Highlands Trail which extends 150 miles from Storm King Mountain on the Hudson River in New York south to Riegelsville on the Delaware River in New Jersey. Blazed with teal-colored diamonds, the trail combines established trails, new trails, and road walking, and displays the scenic beauty of the Highlands region.

FISHING The Spruce Run cuts through the property and is seasonally stocked with trout. Fishermen must display a state fishing license.

HUNTING Hunting is permitted to control the deer population. Hunters must obtain a special permit issued by the Division in order to hunt in the park. Visitors between September and February are strongly encouraged to wear blaze orange or confine visits to Sundays. See additional information on the Hunterdon County Park System Controlled Hunting Program.

SPRUCE RUN RECREATION AREA : Spruce Run Recreation Area, which borders Union Furnace, is maintained by New Jersey’s Division of Parks and Forestry and the Division of Fish and Wildlife. The state park provides a variety of recreational activities including boating, swimming, hiking, and camping. The area managed by the Division of Fish and Wildlife permits hunting to control wildlife populations. Contact the Spruce Run Recreation Area for more information at (908) 638-8572.

WILDLIFE Union Furnace and Spruce Run offer a rich diversity of wildlife. Shorebirds are common along the edge of the reservoir and the Spruce Run. Common Yellowlegs and Least Sandpipers have been observed at these locations. Herring and Ring-billed Gulls are also common sightings. Other birds that have been reported within the preserve include Baltimore Orioles, Blue Jays, and Cedar Waxwings. Union Furnace is also home to other wildlife including raccoons, skunks, opossums, and jumping mice.

With the exception of park properties with reservable facilities, all properties are “carry in / carry out” and trash/recycling receptacles are
not provided. Please plan accordingly and do not leave any trash/recyclables behind.

The Hunterdon County Parks and Recreation Division is dedicated to preserving open space and natural resources, providing safe parks and facilities, and offering educational and recreational opportunities, all contributing to an enhanced quality of life for present and future generations.

Acreage 100
Meeting Room NO
Mountain Biking NO


Canoe Access NO
Cross County Skiing NO
Fishing YES
Fitness Trail NO
Gardens NO
Hiking/Nature Trails YES
Horseshoe Court NO
Horse Trails NO
Hunting YES
Information Boards NO
Nature Study YES
Picnic Pavilions NO
Picnic Sites NO
Playground NO
Restrooms NO
Scenic Vistas NO
Sledding Area NO
Soccer & Baseball/Softball Fields NO
Visitor Center NO
Gazebo NO
Parking YES
Reservable Facility NO

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Union Furnace Preserve is located on Van Syckles Road in Union Township. The park is open from sunrise to sunset. No restroom facilities are available. Parking is located at Spruce Run’s Fishing Access, 15 Van Syckles Road, Clinton 08809.

PHYSICAL ADDRESS 15 Van Syckles Road, Clinton 08809.

Directions from the Flemington Area From the Flemington Circle, take Route 31 north 12.4 miles to Van Syckles Road. Turn left and go a short distance to Spruce Run’s Fishing Access on the left. The Union Furnace entrance is located across Van Syckles Road.

Directions from I - 78 Westbound Take exit 17 (Clinton-Washington Exit) to Route 31 north. Travel 6.6 miles to Van Syckles Road. Proceed as above.

Directions from I - 78 Eastbound Take exit 16 (Washington Exit) to Route 31 north and travel 6.6 miles to Van Syckles Road. Proceed as above.

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A single hiking trail runs through Union Furnace. The trailhead is located across from the Spruce Run Parking Area. Part of the trail incorporates the berm of the old mill raceway. Then it climbs up the hill and emerges onto Serpentine Drive. The trail is part of the Highlands Trail System which is a cooperative effort of the New York/New Jersey Trail Conference. Their goal is to create a trail system that will span the highlands between Hunterdon and Passaic Counties.

Trail Guides are set up with the brochure on one side, and the map on the other.  The brochure should be printed on legal size page, and the map can be printed on standard 8 ½ x 11” paper. 

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It is the policy of the County to provide reasonable accommodations to persons with disabilities upon advance notice of need. Persons  requiring accommodations should make a request at least two weeks prior to program attendance.

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PHYSICAL ADDRESS: Hunterdon County Arboretum, 1020 Highway 31, Lebanon, NJ 08833       MAILING ADDRESS: P.O. Box 2900, Flemington, NJ 08822
PHONE: 908-782-1158       EMAIL:

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