Sinkhole risk in Perry County, AL: Pockets of it

Pockets of it

Soluble rock at the surface or under thin cover in part of the county.

On soluble rock: 29%
At or near the surface: 29%
Buried under cover: 0%

The next step for one property

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 207 of Perry County's 720 square miles on soluble rock, 207 of them with the rock at or near the surface. With about 7,719 residents (11 per square mile), much of the land is open, and the mapped rock may sit far from where people actually live. The figures come from 250 map points about 1.7 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: the signs to look for and how an inspection works, and how these percentages are measured.

Counties around Perry County

The nearest county rated sinkhole country is Noxubee County, MS, about 81 miles northwest. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Hale County, AL 21 mi west · 20% at surface
Dallas County, AL 24 mi southeast · 27% at surface
Bibb County, AL 28 mi north · 12% at surface
Chilton County, AL 36 mi northeast · 6% at surface
Autauga County, AL 38 mi east · 2% at surface
Marengo County, AL 40 mi southwest · 33% at surface

Which formation it is

The largest mapped soluble unit here is the Selma Group; Mooreville Chalk (carbonate), Cretaceous in age, covering about 19% of the county. Next is the Selma Group; Demopolis Chalk at 10%.

Against the rest of Alabama

Perry County ranks 25 of 67 in Alabama for soluble rock at the surface, and sits above 79% of US counties on that measure.