The Chicago Ridge plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.
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74° on Nov. 13, 1989, the hottest reading for this week of the year since 1980. Next is 74° in 2016.
Chicago Ridge’s center stands about 600 ft above sea level. Within three miles the land runs from 590 ft to 690 ft, a difference of 100 ft: gently rolling country.
Under the town center the state geologic map shows Silurian System undivided (dolostone, limestone), from the Silurian, 422 to 445 million years old.
The section below crosses 2 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 64×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Dolostone, limestone. Age: Silurian, 422 to 445 million years old. About 23 mi of the line.
Limestone. Age: Middle Devonian, 384 to 394 million years old. About 1 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale.
Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.
A raindrop that lands in Chicago Ridge reaches the Gulf of America by way of the Calumet Sag Channel, the Chicago Sanitary and Ship Canal, the Des Plaines, the Illinois and the Mississippi: about 1,500 river miles.
Lake on the way: Peoria Lake.
1,190 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Chicago Ridge; river miles along the main stem, rounded.
Chicago Ridge has a hot-summer humid continental climate. Summer afternoons average 85° in July; winter nights fall to about 20° in January. A normal year brings about 39 inches of snow; with the rain, that comes to about 41 inches of water.
On November 14 Chicago Ridge normally reaches 50° and falls to 36°. The record high is 68°, in 2025; the record low 15°, in 1986. The most rain on this date, 1.60 in, fell in 1989.
Normals 1991–2020 and records since 1980 at Chicago Midway Airport 3 SW, 2 miles north. NOAA, through RCC-ACIS.
