Oakdale Nature Preserve 
4433 South Crane's Grove Road
Freeport, IL 61032
815-233-5616

Features 133 acres of oak and hickory woods with three miles of winding trails for hiking and cross-country skiing. Facilities include Bill Gelwicks Nature Center, the Stephen Mogle Environmental Learning Center, a lodge, a dining hall, an auditorium, picnic areas, and shelters.