The Walnut Grove 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.
Walnut Grove’s center stands about 900 ft above sea level. Within three miles the land runs from 750 ft to 970 ft, a difference of 220 ft: rolling country. The highest named summit within 15 miles is Snellville Mountain, about 1,210 ft, 13 miles northwest.
Under the town center the state geologic map shows Granitic Gneiss undifferentiated, from the Precambrian to Paleozoic.
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 49×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Gneiss. Age: Precambrian to Paleozoic. About 19 mi of the line.
Amphibolite, biotite-gneiss, mica-schist. Age: Precambrian to Paleozoic. About 6 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 Walnut Grove reaches the Atlantic Ocean by way of Cornish Creek, the Alcovy, the Ocmulgee and the Altamaha: about 410 river miles.
Lake on the way: Jackson Lake.
240 miles of the trip are on the Ocmulgee.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Walnut Grove; river miles along the main stem, rounded.