Sinkhole risk in Marshall County, TN: Sinkhole country

Sinkhole country

Soluble rock at or near the surface across much of the county.

On soluble rock: 94%
At or near the surface: 94%
Buried under cover: 0%

The next step for one property

Get a sinkhole or geotechnical inspection before buying, building or adding weight to a foundation.

That works out to roughly 354 of Marshall County's 375 square miles on soluble rock, 354 of them with the rock at or near the surface. With about 37,847 residents (101 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 242 map points about 1.2 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: the signs to look for and how an inspection works, and how these percentages are measured.

Counties around Marshall County

The closest county with no soluble rock mapped is Henderson County, TN, about 92 miles west. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Bedford County, TN 18 mi east · 93% at surface
Maury County, TN 20 mi northwest · 84% at surface
Giles County, TN 24 mi southwest · 62% at surface
Lincoln County, TN 25 mi southeast · 62% at surface
Moore County, TN 26 mi southeast · 65% at surface
Williamson County, TN 30 mi north · 72% at surface

The rock underneath

The largest mapped soluble unit here is the Stones River Group; Ridley Limestone (limestone), Ordovician in age, covering about 31% of the county. Next is the Nashville Group; Bigby-Cannon Limestone and Hermitage Formation at 22%.

Against the rest of Tennessee

Marshall County ranks 6 of 95 in Tennessee for soluble rock at the surface, and sits above 98% of US counties on that measure.