Sinkhole risk in Mitchell County, IA: Pockets of it

Pockets of it

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

On soluble rock: 100%
At or near the surface: 0%
Buried under cover: 100%

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 467 of Mitchell County's 469 square miles on soluble rock. With about 10,632 residents (23 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 416 map points about 1.1 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Mitchell County

The nearest county rated sinkhole country is Clayton County, IA, about 82 miles southeast. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Floyd County, IA 20 mi south · 0% at surface
Mower County, MN 22 mi north · 0% at surface
Howard County, IA 23 mi east · 5% at surface
Worth County, IA 23 mi west · 0% at surface
Cerro Gordo County, IA 30 mi southwest · 0% at surface
Chickasaw County, IA 31 mi southeast · 0% at surface

Which formation it is

The largest mapped soluble unit here is the Cedar Valley Limestone (limestone), Middle Dovonian in age, covering about 98% of the county. Next is the Shell Rock Formation at 2%.

Against the rest of Iowa

Mitchell County ranks 68 of 99 in Iowa for soluble rock at the surface, and sits above 0% of US counties on that measure.