This is the loop that connects all of the other trails in the Palos system.
Start at Wolf Road Woods and head north down "Gravity Cavity" and just keep following the trail signs to stay on the Orange Loop
Highlights include the three consecutive ravines along 107th Street, the paved hill coming up from Archer Avenue and a peak at the monument denoting the pile of radioactive waste buried below from the days when this area served as Argonne National Laboratory.
The loop finishes up back at Wolf Road Woods after about a mile of horse trail.
This is the most heavily used trail in the area. There are usually many mountain bikers on the trail at any given time. Keep aware of bikers coming towards you and from behind. It's probably best to leave the headphones at home so you can hear traffic coming from behind you.
Whitetail deer, dragonflies, raccoons, toads, and the occasional coyote.