The De Graff 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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1° on Nov. 16, 1933, the coldest reading for this week of the year since 1894. Next is 4° in 2019.
De Graff’s center stands about 1,010 ft above sea level. Within three miles the land runs from 970 ft to 1,090 ft, a difference of 120 ft: gently rolling country. The highest named summit within 15 miles is Campbell Hill, about 1,550 ft, 11 miles east-northeast.
Under the town center the state geologic map shows Salina Group (dolostone), from the Silurian, 422 to 445 million years old.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 36×. 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. Age: Silurian, 422 to 445 million years old. About 12 mi of the line.
Dolostone. Age: Silurian, 425 to 445 million years old. About 4 mi of the line.
Shale, black-shale. Age: Devonian, 359 to 422 million years old. About 3 mi of the line.
Shale, dolostone, limestone. Age: Ordovician, 445 to 487 million years old. About 2 mi of the line.
Dolostone, limestone, shale. Age: Silurian, 422 to 445 million years old. About 2 mi of the line.
Dolostone. Age: Silurian, 428 to 445 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 De Graff reaches the Gulf of America by way of Bokengehalas Creek, the Great Miami, the Ohio and the Mississippi: about 1,600 river miles.
970 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of De Graff; river miles along the main stem, rounded.
De Graff has a hot-summer humid continental climate. Summer afternoons average 83° in July; winter nights fall to about 18° in January. About 43 inches of rain fall in a normal year.
On November 14 De Graff normally reaches 50° and falls to 32°. The record high is 72°, in 1931; the record low 8°, in 2019. The most rain on this date, 1.77 in, fell in 1993.
Normals 1991–2020 and records since 1894 at Bellefontaine, 8 miles east-northeast, 170 ft higher. NOAA, through RCC-ACIS.
