Sinkhole risk in Thomas County, GA: Pockets of it

Pockets of it

Soluble rock at the surface or under thin cover in part of the county.

On soluble rock: 100%
At or near the surface: 34%
Buried under cover: 67%

What this means before you buy

Check the parcel against your state survey sinkhole map, and ask for an inspection if cracks, depressions or sticking doors show up.

That works out to roughly 545 of Thomas County's 545 square miles on soluble rock, 182 of them with the rock at or near the surface. With about 46,054 residents (85 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 337 map points about 1.3 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Thomas County

The nearest county rated sinkhole country is Mitchell County, GA, about 30 miles northwest, close enough that the same rock may run under the county line. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Grady County, GA 19 mi west · 29% at surface
Brooks County, GA 20 mi east · 29% at surface
Colquitt County, GA 24 mi north · 21% at surface
Mitchell County, GA 30 mi northwest · 66% at surface
Jefferson County, FL 32 mi south · 46% at surface
Leon County, FL 35 mi southwest · 43% at surface

The rock underneath

The largest mapped soluble unit here is the "Hawthorn Formation" (sand), Miocene in age, covering about 67% of the county. Next is the "Hawthorn Formation" at 34%.

The county also lies over the Floridan shelf, a deep salt or gypsum basin. Deep beds rarely cause surface collapse on their own, but wells and mining into them have.

Against the rest of Georgia

Thomas County ranks 27 of 159 in Georgia for soluble rock at the surface, and sits above 81% of US counties on that measure.