Big Four Reservoir (historical)
Reservoir in Montgomery County, Illinois · on the USGS Hillsboro quadrangle
39.16251, -89.46304
Maps that show Big Four Reservoir (historical)
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Hillsboro, IL
Detailed map of terrain, trails and roads
USGS topo, 2024
Hillsboro, IL
Old map for history, not navigation
USGS historical 15-minute topo (1947)
Hillsboro, IL
Old map for history, not navigation
USGS historical 15-minute topo (1949)
Network to Freedom Brochure Map - National Underground Railroad Network to Freedom Program
National Park Service Maps · National Underground Railroad Network to Freedom Program
U.S. Fish and Wildlife Service Alligator Snapping Turtle Range (2024)
Fish & Wildlife Service Refuge Maps
Bureau of Land Management Eastern States Overview map
BLM Eastern States (2019)
IFR Enroute Low Altitude Chart L-27 (U.S.)
FAA, 2026-10-29
IFR Enroute High Altitude Chart H-05 (U.S.)
FAA, 2026-10-29
Nearby
Name, class, county and location: USGS Geographic Names Information System (public domain).