This trail system is a work in progress by the Tri-County Mountain Bike Association. It is for members only; however 2 day memberships are available at the kiosk. There is 6.2 miles of singletrack thus far and has separate beginner, advanced and expert sections making it fun for any skill level. There is an awesome tree bridge for the more advance riders. The scenery is beautiful with plenty of large rock formations.
Exit I-55 @ Old Agency Road, turn right (North) onto Highland Colony Parkway, turn left at the 2nd 4-way stop onto Lake Castle Road, eventually turn right onto North Livingston Road then turn left onto Giles Lane (entrance to the Springbrook Farms subdivision), after a wide turn in Giles Lane look for slag driveway on the left, follow slag road to trail head and kiosk with maps and membership information.
http://www.singletracks.com/item.php?c=1&i=1947