Base compiled in 1976 from USGS 1:24,000-scale topographic maps dated 1954-1974, revised from aerial photographs taken 1976; interpretations derived from soil map constructed 1974.; "Projection and 10 000-meter grid ticks: Universal Transverse Mercator ..."; "25 000-foot grid ticks based on Illinois coordinate system, west zone."; May 1979.; Includes location map.
53 x 62 centimeters
Scale 1:100,000