Pennsylvania Gulch

To reach Pennsylvania Gulch, typically driven uphill from Sunset: From Boulder, take Highway 119 (Boulder Canyon Drive) west towards Nederland. Turn right onto Fourmile Canyon Road (County Road 118). Follow Fourmile Canyon Road to the small town of Sunset. In Sunset, turn left onto County Road 93. Proceed for a very short distance (less than 0.2 miles) to the first switchback. The entrance to Pennsylvania Gulch trail (C.R. 95J) will be on your right. Alternatively, it can be accessed as a turn-off from the Switzerland Trail system just south of Sunset. The trail ends at Highway 72 (Peak to Peak Highway). The approximate GPS coordinates for the Sunset-side trailhead are 40.019374, -105.493314.

Pennsylvania Gulch is rated as difficult and will test your vehicle and driving skills. Expect a consistently rocky and steep path, with sections featuring deep ruts, exposed tree roots, and large, loose rocks due to significant erosion. The trail is a very narrow shelf road for most of its length, offering very few places to pass oncoming vehicles; caution, patience, and communication with other drivers are key. Uphill traffic (from Sunset towards Highway 72) always has the right-of-way, and if you choose to drive downhill, be prepared to back up for considerable distances on challenging terrain. Some specific obstacles, like a water pipe crossing the trail, can create slick conditions and cause your vehicle to lurch unexpectedly. While there may not be single extreme obstacles, the combination of the trail's narrowness, steep grades, loose surfaces, and ongoing erosion demands careful tire placement and a capable 4x4 vehicle. Lifted vehicles with larger tires and good articulation are beneficial. Stock vehicles may struggle, and there's a risk of undercarriage damage. Lockers can be helpful in some sections.