Base compiled in 1976 from USGS 1:24,000-scale topographic maps dated 1954-1973, revised from aerial photographs taken 1975; interpretations derived from soil map constructed 1974.; "Projection and 10 000-meter grid ticks, zone 16: Universal Transverse Mercator."; "25 000-foot grid ticks based on Illinois coordinate system, east zone."; May 1979.; Includes location map.
38 x 43 centimeters
1:100,000