Sinkhole risk in Blount County, TN: Sinkhole country

Sinkhole country

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

On soluble rock: 58%
At or near the surface: 58%
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 324 of Blount County's 559 square miles on soluble rock, 324 of them with the rock at or near the surface. With about 142,211 residents (254 per square mile), homes are spread across towns and farmland, and a mapped unit may or may not reach the developed parts. The figures come from 257 map points about 1.5 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Blount County

The closest county with no soluble rock mapped is Graham County, NC, about 24 miles south. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Knox County, TN 21 mi north · 95% at surface
Loudon County, TN 22 mi west · 99% at surface
Sevier County, TN 23 mi east · 36% at surface
Graham County, NC 24 mi south · 0% at surface
Monroe County, TN 25 mi southwest · 37% at surface
Swain County, NC 27 mi east · 2% at surface

What Blount County is built on

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 10% of the county. Next is the Sevier Shale at 8%.

Against the rest of Tennessee

Blount County ranks 45 of 95 in Tennessee for soluble rock at the surface, and sits above 89% of US counties on that measure.