Sensational September! Let’s Go Hiking!

Sourland Mountain Preserve

Hike over boardwalks and through the boulders of Devil’s Half Acre and Roaring Rocks.

5.4 miles. Very rocky with some minor elevation gain. Mountain biking, horseback riding, and bouldering are also allowed.

Our two cents:

A solid loop with plenty of interesting rock formations. Though the trail requires no scrambling, bouldering is allowed here so energetic hikers can clamber around the big rocks in Devil’s Half-Acre.

Even though there’s a “Ridge” trail, there are no views from any of the trails. From info located online, this appears to be a no-hunting park.

Updates – 5/2021: Description and Interactive Map updated to reflect major trail system changes; but not re-hiked.

1/2021 – While trail locations are unchanged the park has completely changed the trail markings: circle and squares are now painted blazes, “C” connector trails are now blazes with dots, position of numbered signs has changed, and some trail names have been changed. Older change logs at bottom of page.


Print out the map from the park site, and maps may be in the trail kiosk. Follow along on a smartphone with our Interactive Map link in the box above.

NOTE! There have been changes made to the trail system here. The description below has been updated, but we’ve not done this hike since the changes.


This route now appears in Best Day Hikes in New Jersey and Hike of the Week. Variations can be found in Best Day Hikes Near Philadelphia and 60 Hikes Within 60 Miles: New York City.

Parking: N40.47380° W74.69425°

East Mountain Road, Hillsborough, NJ 08844. Directions can be found on the park site.


Porta-john in the parking lot.

Hike Directions:

Overview: ORANGE (Maple Flats) – YELLOW (Devil’s Half-Acre) – WHITE (Tributary) – RED (Ridge) – BLUE (Roaring Rocks) – WHITE (Tributary) – ORANGE (Maple Flats)

** Due to the changes to the trails in this park, the trail markings shown in our photos will not match what the description states. **

0.0 – The trailhead for all trails starts behind the trail kiosk, near the tree line. Start following ORANGE (Maple Flats).

Main trailhead

0.2 – Start following YELLOW (Devil’s Half-Acre) straight, passing Marker #1 and a bridge on the left. [ORANGE (Maple Flats) goes left.]

Ridge Trail

Continue following YELLOW (Devil’s Half-Acre), passing YELLOW DOT (Devils’s Half-Acre Connector) on the left.

The trail heads uphill and loops around an area of large boulders.

Ridge Trail thru Devil's Half Acre Boulders
Devil's Half Acre Boulders
Ridge Trail marker

Continue following YELLOW (Devil’s Half-Acre), passing the other end of YELLOW DOT (Devils’s Half-Acre Connector) on the left.

Large boulder in Devil's Half Acre
Tree growing out of a boulder

1.6 – Marker #3. Start following WHITE (Tributary). [YELLOW (Devil’s Half-Acre) continues].

Shortly, the trail splits in a “Y”. Veer RIGHT to start following RED (Ridge). [WHITE (Tributary) continues off to the left].

Roaring Brook Trail
Rocks of the Roaring Brook Trail

2.1 – Cross a pipeline cut.

Looking up the Pipeline cut

2.3 – Continue following RED (Ridge) to the RIGHT. [RED DOT (Ridge Connector) starts to the left].

// Variation: Instead, start following RED DOT (Ridge Connector). Taking RED DOT doesn’t change the total hike distance. End up back on this route at the next step. What is now RED DOT used the be the main RED trail, and is the original route of our hike guide. We changed the hike to stick to RED to simplify things. //

3.0 – Marker #4. Start following BLUE (Roaring Rocks) to the right. [RED (Ridge) ends. RED DOT (Ridge Connector) is on the left. BLUE (Roaring Rocks) also goes left.]


3.1 – Continue on BLUE (Roaring Rocks), passing BLUE DOT (Roaring Rocks Connector) on the left.

Ridge Trail

3.2 – Marker #5, near a very large cairn (hiker pile-o-rocks). Start following WHITE (Tributary) ahead. [BLUE (Roaring Rocks) and WHITE (Tributary) also go to the left, towards Marker #6].

Huge cairn near Marker 7, Ridge Trail

Follow WHITE (Tributary) down several gradual switchbacks before the trail levels out and arrives at an opening in a chain-link fence.

Flat rocks on the trail

3.6 – Walk through the fence opening and continue straight on WHITE (Tributary). [WHITE DOT (Tributary Connector) goes left, also leading to Marker #7]

4.0 – Marker #7. Continue straight on WHITE (Tributary). [WHITE DOT(Tributary Connector) goes left].

Pass stone remnants of a structure. There are several boardwalks and stone pathways in wet areas.

Boardwalk on the ridge trail
Bridge on the ridge trail

4.7 – Marker #8. Turn RIGHT, to now follow ORANGE (Maple Flats). [ORANGE (Maple Flats) also continues ahead. WHITE (Tributary) ends].

Cross the pipeline cut and ORANGE (Maple Flats) continues on the other side.

Crossing the pipeline again

5.2 – Continue on ORANGE (Maple Flats) as it turns RIGHT, passing ORANGE DOT (Maple Flats Connector).

Head towards a pond on a grassy area in a field.

Approaching the pond near the parking lot

At the pond, the parking lot will be visible off to the left.