If you're looking for a fun ride on your ATV in Pennsylvania, check out Allegheny National Forest. This historic forest has several different ATV trails for you to enjoy.
The Marienville trail is shared with mountain bikes, but don't let that stop you from riding your ATV there. There are about 35-miles of trails that interconnect and it's a good winding ride. Rocky Gap ATV Trail is about 20-miles in length and there is a designated trailhead, however it is permissible to access this trail anywhere it crosses a public road.
Timberline ATV Trail is located just south of the Rocky Gap Trail System and is a great ride. Just like Rocky Gap, you can either enter this trail at the trailhead or anywhere it crosses a public road. This trail also connects to the Marienville ATV Trail if you're interested in crossing over at any point when you're planning your ATV ride. Willow Creek ATV Trail is a 10.8 mile loop trail located along Forest Road (FR) 137, approximately two miles south of SR 346 and 11 miles west of Bradford. All of these trails are multi-use trails and traffic will include snowmobiles during the colder months, hikers, and mountain bikes.
If you want to make a long weekend out of it, camping is permitted as long as you are not on the shores and you stay within 1500 feet inland of the timberline around the Allegheny Reservoir, this applies for all areas except designated campsites.