Sinkhole risk in Lincoln County, TN: Sinkhole country

Sinkhole country

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

On soluble rock: 62%
At or near the surface: 62%
Buried under cover: 0%

What to do about a house in Lincoln County

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

That works out to roughly 355 of Lincoln County's 570 square miles on soluble rock, 355 of them with the rock at or near the surface. With about 36,751 residents (64 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 300 map points about 1.4 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 Lincoln County

The closest county with no soluble rock mapped is Cullman County, AL, about 72 miles south. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Moore County, TN 17 mi northeast · 65% at surface
Marshall County, TN 25 mi northwest · 94% at surface
Giles County, TN 25 mi west · 62% at surface
Madison County, AL 26 mi south · 59% at surface
Bedford County, TN 27 mi north · 93% at surface
Franklin County, TN 28 mi east · 66% at surface

What Lincoln County is built on

The largest mapped soluble unit here is the Ordovician [units] including Richmond Group (which includes Mannie Shale, Fernvale Limestone, Sequatchie Formation, and Arnheim Formation), the Maysville Group (which includes Leipers Formation), the Eden Group (which includes Inman Formation), and (shale), Ordovician in age, covering about 35% of the county. Next is the Nashville Group; Bigby-Cannon Limestone and Hermitage Formation at 19%.

Against the rest of Tennessee

Lincoln County ranks 41 of 95 in Tennessee for soluble rock at the surface, and sits above 91% of US counties on that measure.