Sinkhole risk in Camden County, GA: Mostly deep or small

Mostly deep or small

Some soluble rock, mostly deeply buried or in a small share of the county.

On soluble rock: 24%
At or near the surface: under 1%
Buried under cover: 24%

What to do about a house in Camden County

Sinkholes are uncommon here; watch for new depressions after heavy rain or leaking pipes.

That works out to roughly 152 of Camden County's 630 square miles on soluble rock, 3 of them with the rock at or near the surface. With about 59,099 residents (94 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 274 map points about 1.5 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why gypsum and salt move faster than limestone, and why the 24% under cover still counts.

Counties around Camden County

The nearest county rated sinkhole country is Nassau County, FL, about 22 miles south, close enough that the same rock may run under the county line. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Glynn County, GA 22 mi northeast · 0% at surface
Nassau County, FL 22 mi south · 67% at surface
Brantley County, GA 28 mi northwest · under 1% at surface
Charlton County, GA 31 mi west · 1% at surface
Duval County, FL 40 mi south · 30% at surface
McIntosh County, GA 43 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 23% of the county. Next is the Hawthorn Group, Coosawhatchie Formation, Charlton Member at under 1%.

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

Camden County ranks 69 of 159 in Georgia for soluble rock at the surface, and sits above 52% of US counties on that measure.