Sinkhole risk in Crittenden County, KY: Sinkhole country

Sinkhole country

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

On soluble rock: 66%
At or near the surface: 66%
Buried under cover: under 1%

The next step for one property

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

That works out to roughly 237 of Crittenden County's 360 square miles on soluble rock, 236 of them with the rock at or near the surface. With about 8,982 residents (25 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 433 map points about 0.9 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why gypsum and salt move faster than limestone, and the signs to look for and how an inspection works.

Counties around Crittenden County

The closest county with no soluble rock mapped is Union County, KY, about 22 miles north. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Hardin County, IL 14 mi northwest · 61% at surface
Livingston County, KY 18 mi southwest · 54% at surface
Caldwell County, KY 19 mi southeast · 74% at surface
Union County, KY 22 mi north · 0% at surface
Lyon County, KY 23 mi south · 58% at surface
Pope County, IL 24 mi west · 19% at surface

Which formation it is

The largest mapped soluble unit here is the Ste. Genevieve and St. Louis Limestones, undivided (limestone), Mississippian in age, covering about 24% of the county. Next is the Rocks of Chesterian age, lower part at 24%.

The county also lies over the Illinois Basin, 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 Kentucky

Crittenden County ranks 24 of 120 in Kentucky for soluble rock at the surface, and sits above 91% of US counties on that measure.