Southeast of Pittsburgh and Donegal in the Forbes State Forest, the 10+ mile Mountain Streams Trail System is open to mountain biking. The backbone of the system is the 7.7 mile Mountain Streams Trail. There are several trailheads located on SR31.
To reach the trailheads near Jones Mills from the Pennsylvania Turnpike (US70/US76), use Exit #91. Head east on SR31. There is a trailhead in Jones Mills and then another trailhead just past Jones Mills.
Overall, Mountain Streams Trail System is the 57th most popular mountain bike trail of all 75 mountain biking rides in Pennsylvania.