Sinkhole risk in Loudon County, TN: Sinkhole country

Sinkhole country

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

On soluble rock: 99%
At or near the surface: 99%
Buried under cover: 0%

What to do about a house in Loudon County

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

That works out to roughly 227 of Loudon County's 229 square miles on soluble rock, 227 of them with the rock at or near the surface. With about 62,129 residents (271 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 499 map points about 0.7 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Loudon County

The closest county with no soluble rock mapped is Morgan County, TN, about 33 miles northwest. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Roane County, TN 14 mi northwest · 74% at surface
Monroe County, TN 20 mi south · 37% at surface
Blount County, TN 22 mi east · 58% at surface
Anderson County, TN 27 mi north · 50% at surface
McMinn County, TN 27 mi southwest · 86% at surface
Knox County, TN 28 mi northeast · 95% at surface

Which formation it is

The largest mapped soluble unit here is the Unnamed (upper part of Knox Group), including Newala Formation, Mascot Dolomite, Kingsport Formation, Longview Dolomite, and Chepultepec Dolomite (dolostone (dolomite)), Ordovician in age, covering about 32% of the county. Next is the Copper Ridge Dolomite at 27%.

Against the rest of Tennessee

Loudon County ranks 3 of 95 in Tennessee for soluble rock at the surface, and sits above 99% of US counties on that measure.