Sinkhole risk in Overton County, TN: Sinkhole country

Sinkhole country

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

On soluble rock: 66%
At or near the surface: 66%
Buried under cover: 0%

What to do about a house in Overton County

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

That works out to roughly 287 of Overton County's 433 square miles on soluble rock, 287 of them with the rock at or near the surface. With about 23,551 residents (54 per square mile), much of the land is open, and the mapped rock may sit far from where people actually live. The figures come from 277 map points about 1.3 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 Overton County

The closest county with no soluble rock mapped is Morgan County, TN, about 39 miles east. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Putnam County, TN 18 mi southwest · 60% at surface
Pickett County, TN 19 mi northeast · 56% at surface
Fentress County, TN 19 mi east · 15% at surface
Clay County, TN 20 mi northwest · 39% at surface
Jackson County, TN 22 mi west · 58% at surface
Clinton County, KY 28 mi north · 75% at surface

Which formation it is

The largest mapped soluble unit here is the St. Louis Limestone and Warsaw Limestone (limestone), Mississippian in age, covering about 38% of the county. Next is the Monteagle Limestone at 15%.

Against the rest of Tennessee

Overton County ranks 36 of 95 in Tennessee for soluble rock at the surface, and sits above 92% of US counties on that measure.