See reviews below.
From <a href="http://www.cambr.org/" class="toplink2">cambr.org</a>: Take I-55 past I-355 to Weber Road. Go north to Naperville Road and turn left for a few miles. You have two parking choices:<br /><br />1. At Royce Road, you'll see the DuPage County Park on your left. Turn in here and park by the treeline ahead of you. Ride along the treeline and you'll quickly see a trail on your right into the woods.<br /><br />2. If weekend sports events fill up that lot, drive on to Washington Avenue and take a left. Go two blocks to Ring Road, turn left, then left again at the next street, Knox Knoll Dr. Go one mile until you see the entrance to the park on the left. Park at the end of the lot. Cross the small and large bridge to get to the trails.
http://www.singletracks.com/item.php?c=1&i=119