New Jersey Butterfly Sites

Sourland Mountain Preserve

by Keith Richmond

County: Somerset.

Municipality: Hillsborough Township.

Directions: From the north, take Interstate 287 – from the east or west, take US 22 to the Bridgewater / Somerville area. Exit onto US 206/202 south. At the Somerville “circle” where 202 and 206 split, continue south on US 206 for 5.6 miles to Mountain View Road. At this light (there are 2 gas stations here), turn right and at the end of the road you will reach East Mountain Road. Turn left and in 0.8 miles the entrance driveway will be on your right.

From the south follow Route 206 north through Princeton and Montgomery. In less than 1 mile after entering Hillsborough, you will reach the light at Mountain View Road. Turn left here and follow the directions above.

Parking: Yes. A large gravel parking lot is found at the end of the entrance driveway.

Nearest sizable town: Gas stations are located at the corner of US 206 and Mountain View Road, while a deli, pizza restaurant, and a diner are found just north of this intersection. Many more options exist several miles north in Hillsborough and south in Montgomery Township.

Habitats: The 4,000 acre Sourland Mountain Preserve is owned by the Somerset County Park Commission. The Preserve provides passive recreational opportunities in an undisturbed natural setting. Sourland Mountain is a mostly forested diabase rock outcropping rising to a height of just over 500 feet. The preserve is bisected by the Texas Eastern gas pipeline.

Maintained/Marked trails: Yes. A trail map is available. The trail which climbs the mountain following the pipeline cut provides the best butterfly habitat. Follow this trail to the top and return as you came, unless you prefer to explore one of several intersecting trails in search of birds or other woodland species. Please note that Black Cohosh, the foodplant for Appalachian Azure caterpillars may be found as a tall understory plant along some of the woodland trails.

Restrooms: Porta-A-Johns can be found next to the kiosk in the parking lot.

Picnic tables: No.

Notable species: Banded Hairstreak, Hickory Hairstreak, Red-banded Hairstreak, Appalachian Azure, Great Spangled Fritillary, Hackberry Emperor, Appalachian Brown, Dreamy Duskywing, Little Glassywing and Pepper and Salt Skipper.

Best time to visit: Mid-May through Mid-July corresponding with the bloom of both the dogbane and milkweed found in the pipeline cut.

Exploring Sourland Mountain Preserve: From the main parking lot, head south around the west (right) side of the pond. As you reach the southwest corner of the pond, you will come to an opening through the tree line, then down a small hill leading to the Texas Eastern gas pipeline.

Special precautions: The lower portion of the trail can be wet and muddy in spots – proper footwear is advised. Once the trail begins to climb the mountain, several sections are fairly steep.

You might also want to visit: Duke Farms.

Further information about Sourland Mountain Preserve is available



To view a larger map, click on 'View larger map' icon in upper right hand corner. (Tip: The satellite view may also suggest good potential butterfly habitat to explore.)


Sourland Mountain Sign

Sourland Mountain Preserve sign.


Sourland Mountain Pond and Parking Lot

Sourland Mountain Preserve pond and main parking lot.


Sourland Mountain Pipeline

Sourland Mountain Preserve pipeline trail uphill looking southwest.


Sourland Mountain Pipeline

Sourland Mountain Preserve pipeline trail looking northeast.