Sinkhole risk in Chickasaw County, IA: 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: 100%
At or near the surface: 0%
Buried under cover: 100%

What to do about a house in Chickasaw County

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

That works out to roughly 504 of Chickasaw County's 504 square miles on soluble rock. With about 11,719 residents (23 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 400 map points about 1.1 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why the 100% under cover still counts, and how these percentages are measured.

Counties around Chickasaw County

The nearest county rated sinkhole country is Clayton County, IA, about 52 miles east. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Bremer County, IA 19 mi south · 0% at surface
Howard County, IA 21 mi north · 5% at surface
Floyd County, IA 24 mi west · 0% at surface
Fayette County, IA 28 mi southeast · 19% at surface
Winneshiek County, IA 28 mi northeast · 18% at surface
Mitchell County, IA 31 mi northwest · 0% at surface

What Chickasaw County is built on

The largest mapped soluble unit here is the Cedar Valley Limestone (limestone), Middle Dovonian in age, covering about 100% of the county.

Against the rest of Iowa

Chickasaw County ranks 31 of 99 in Iowa for soluble rock at the surface, and sits above 0% of US counties on that measure.