Power Island & Undermine Loop Mountain Bike Trails

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Scenic singletrack loops that travel along the river, over bridges, and through a wide variety of forest types.
Trail Activity
Mountain biking
3.0 miles, Network
Gorham (NH)
Packed Earth/Dirt, Gravel/Crushed Stone/Cinder
Permitted on leash
Other Activities


The Power Island and Undermine Loop mountain bike trails are singletrack trails built for mountain bikes. The trails begin at a trestle bridge which offers spectacular mountain and river views. On Power Island (a man-made island formed by a canal that diverts water from the river to a hydroelectric dam), a single track loop twists and turns,  through dips and up rock garden climbs. The trail travels through pine groves and a variety of other forest types.

The Undermine Loop connects to the Power Island Loop via the Presidential Rail Trail. It is a winding roller coaster of singletrack and narrow bridges.

Other Information

These mountain biking trails are part of a growing purpose-built mountain biking network maintained by the Coos Cycling Club, a non-profit organization dedicated to growing the mountain biking community through trail-building, group rides for all levels and ages, and vibrant events.

Trail Manager

The trail is maintained by the Coos Cycling Club. For more information, visit their website or contact: 

Coos Cycling Club
Gorham, NH 03581
View website
Brookfield Renewable Power Company
View website

Trail Tips

Plan Ahead and Prepare
Know how to choose and use your gear for each trip, factoring in the terrain and conditions.

Trailhead Information

Parking is available at the trestle bridge 0.3 miles up NH-16 (Main Street) from the junction with US-2 in the center of Gorham. To reach the Power Island trail from the parking lot, cross the metal grating over the Androscoggin to Power Island on the Presidential Rail Trail. To get to the Undermine Loop, take the Presidential Rail Trail over the Androscoggin on the east side of Power Island.

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