Map
Existing and proposed watersheds, North-South Tollway planMarch 1 1986
Illinois State Toll Highway Authority
Map
Hidden Lake Forest Preserve [Exhibit 1: Arboretum-Forest Preserve District Cooperative Research Program Space Study]April 1984
Forest Preserve District of DuPage County
Map
Hidden Lake Forest Preserve, Exhibit 1: Arboretum-Forest Preserve District Cooperative Research Program Space StudyApril 23 1985
Forest Preserve District of DuPage County