Southeast of Pittsburgh near Somerset, the Forbes State Forest has a great 92 mile network of mountain bike trails. A prime section is located near the Hidden Valley ski resort barn.
To reach the mountain biking trailhead from the PA Turnpike, use Exit #9 (Donegal). Head east on SR31 for six miles. Park near barn just past resort.
Overall, Forbes State Forest is the 10th most popular mountain bike trail of all 75 mountain biking rides in Pennsylvania.