Sinkhole risk in Long 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: 95%
At or near the surface: 0%
Buried under cover: 95%

What to do about a house in Long County

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 381 of Long County's 400 square miles on soluble rock. With about 20,439 residents (51 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 442 map points about 1.0 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why the 95% under cover still counts, and the signs to look for and how an inspection works.

Counties around Long County

The nearest county rated sinkhole country is Nassau County, FL, about 79 miles south. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Wayne County, GA 17 mi southwest · 0% at surface
Liberty County, GA 17 mi east · 0% at surface
Bryan County, GA 26 mi northeast · under 1% at surface
Tattnall County, GA 28 mi northwest · 0% at surface
McIntosh County, GA 28 mi southeast · 0% at surface
Evans County, GA 29 mi north · 0% at surface

Which formation it is

The largest mapped soluble unit here is the Charlton Formation and Duplin Marl (limestone), Pliocene in age, covering about 93% of the county. Next is the "Hawthorn Formation" at 2%.

Against the rest of Georgia

Long County ranks 120 of 159 in Georgia for soluble rock at the surface, and sits above 0% of US counties on that measure.