Sinkhole risk in Charlton 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: 1%
Buried under cover: 99%

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 780 of Charlton County's 780 square miles on soluble rock, 9 of them with the rock at or near the surface. With about 13,021 residents (17 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 521 map points about 1.2 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Charlton County

The nearest county rated sinkhole country is Nassau County, FL, about 25 miles southeast, close enough that the same rock may run under the county line. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Ware County, GA 25 mi northwest · 0% at surface
Nassau County, FL 25 mi southeast · 67% at surface
Brantley County, GA 30 mi north · under 1% at surface
Camden County, GA 31 mi east · under 1% at surface
Baker County, FL 33 mi south · 21% at surface
Clinch County, GA 35 mi west · 0% at surface

What Charlton County is built on

The largest mapped soluble unit here is the Charlton Formation and Duplin Marl (limestone), Pliocene in age, covering about 71% of the county. Next is the "Hawthorn Formation" at 28%.

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

Charlton County ranks 63 of 159 in Georgia for soluble rock at the surface, and sits above 56% of US counties on that measure.