The New Grand Chain 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.
Sunny
Mostly sunny; warmer
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12° on Nov. 13, 2019, the coldest reading for this week of the year since 1923. Next is 16° in 1997.
New Grand Chain’s center stands about 400 ft above sea level. Within three miles the land runs from 280 ft to 450 ft, a difference of 170 ft: gently rolling country. The highest named summit within 15 miles is Burner Hill, about 630 ft, 15 miles west.
Under the town center the state geologic map shows Cretaceous undivided (sandstone, shale), from the Late Cretaceous, 66 to 84 million years old.
The section below crosses 5 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.
Sandstone, shale. Age: Late Cretaceous, 66 to 84 million years old. About 8 mi of the line.
Sand, silt. Age: Pleistocene to Holocene, less than 2.6 million years old. About 6 mi of the line.
Limestone, sandstone, shale. Age: Middle Mississippian, 331 to 347 million years old. About 4 mi of the line.
Limestone. Age: Middle Mississippian, 331 to 347 million years old. About 3 mi of the line.
Limestone, sandstone, shale. Age: Late Mississippian, 324 to 331 million years old. About 2 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 New Grand Chain reaches the Gulf of America by way of Limekiln Slough, the Cache and the Mississippi: about 1,020 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of New Grand Chain; river miles along the main stem, rounded.
New Grand Chain has a humid subtropical climate. Summer afternoons average 89° in July; winter nights fall to about 26° in January. A normal year brings about 7 inches of snow; with the rain, that comes to about 49 inches of water.
On November 14 New Grand Chain normally reaches 58° and falls to 39°. The record high is 75°, in 1999; the record low 14°, in 2019. The most rain on this date, 1.04 in, fell in 2024.
Normals 1991–2020 and records since 1923 at Olmsted Lock And Dam, 6 miles south-southwest. NOAA, through RCC-ACIS.
