Waterfall Glen Forest Preserve is a standout hiking destination in Darien, IL, covering 9.5 miles with 200ft of elevation change. Stats: 9.5 miles, 200ft gain, Easy. Type: Loop. Surface: Paved. Time: 4 hours. Fee: Free. Dogs: Yes, on leash. Permit: No. Wildlife: deer, foxes, herons. Best seasons: Forest preserve surrounding Argonne National Lab. 0.0014. Pack water, layers, and appropriate footwear. Conditions vary across IL. Leave No Trace: stay on trail, pack out all waste, respect wildlife.