Willowbrook Wildlife Center is a 0.7 mile moderately trafficked loop trail located near Glen Ellyn, Illinois that features a lake and is good for all skill levels. The trail is primarily used for hiking, walking, nature trips, and birding and is accessible from March until October.
Only negative here is that it's a small place. They have a wildlife hospital and rehabilitation center, mini zoo with all the animals that come in (from bald eagles to bobcats), visitor center, nature trail, you can 'adopt' the animals to help pay for their food/shelter and such, Even had a staff member outside with a great horned owl that had a messed up eye educating everyone them. Really a small little gem out there.