Sinkhole risk in Rankin County, MS: 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: 13%
At or near the surface: 13%
Buried under cover: 0%

What this means before you buy

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

That works out to roughly 98 of Rankin County's 776 square miles on soluble rock, 98 of them with the rock at or near the surface. With about 160,573 residents (207 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 283 map points about 1.7 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 how these percentages are measured.

Counties around Rankin County

The nearest county rated sinkhole country is Noxubee County, MS, about 99 miles northeast. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Simpson County, MS 25 mi south · 0% at surface
Madison County, MS 26 mi north · under 1% at surface
Scott County, MS 26 mi northeast · 7% at surface
Hinds County, MS 30 mi west · 24% at surface
Smith County, MS 31 mi southeast · 13% at surface
Copiah County, MS 40 mi southwest · 0% at surface

What Rankin County is built on

The largest mapped soluble unit here is the Vicksburg group and Chickasawhay limestone (limestone), Oligocene in age, covering about 13% of the county.

The county also lies over the Gulf Coast salt domes, 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 Mississippi

Rankin County ranks 22 of 82 in Mississippi for soluble rock at the surface, and sits above 70% of US counties on that measure.