Sinkhole risk in Pontotoc County, MS: Sinkhole country

Sinkhole country

Soluble rock at or near the surface across much of the county.

On soluble rock: 82%
At or near the surface: 82%
Buried under cover: 0%

What to do about a house in Pontotoc County

Get a sinkhole or geotechnical inspection before buying, building or adding weight to a foundation.

That works out to roughly 408 of Pontotoc County's 498 square miles on soluble rock, 408 of them with the rock at or near the surface. With about 32,014 residents (64 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 392 map points about 1.1 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Pontotoc County

The closest county with no soluble rock mapped is Yalobusha County, MS, about 40 miles west. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Union County, MS 18 mi north · 75% at surface
Lee County, MS 21 mi east · 62% at surface
Chickasaw County, MS 21 mi south · 93% at surface
Calhoun County, MS 26 mi southwest · 6% at surface
Lafayette County, MS 27 mi west · 1% at surface
Tippah County, MS 38 mi north · 60% at surface

The rock underneath

The largest mapped soluble unit here is the Porters Creek formation (clay or mud), Paleocene in age, covering about 36% of the county. Next is the Ripley formation at 21%.

Against the rest of Mississippi

Pontotoc County ranks 5 of 82 in Mississippi for soluble rock at the surface, and sits above 95% of US counties on that measure.