The Troy 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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Partly cloudy; warmer
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Troy’s center stands about 550 ft above sea level. Within three miles the land runs from 460 ft to 680 ft, a difference of 220 ft: rolling country. The highest named summit within 15 miles is Bald Knob, about 780 ft, 14 miles northeast.
Under the town center the state geologic map shows Meramecian Series (limestone), from the Carboniferous, 324 to 359 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 38×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Limestone. Age: Carboniferous, 324 to 359 million years old. About 14 mi of the line.
Limestone. Age: Carboniferous, 324 to 359 million years old. About 4 mi of the line.
Limestone. Age: Middle Ordovician to Late Ordovician, 445 to 471 million years old. About 4 mi of the line.
Limestone, siltstone. Age: Carboniferous, 324 to 359 million years old. About 2 mi of the line.
Limestone, sandstone. Age: Early Devonian to Late Devonian, 359 to 422 million years old. About 0.3 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 Troy reaches the Gulf of America by way of Buchanan Creek, the Cuivre and the Mississippi: about 1,240 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Troy; river miles along the main stem, rounded.
