Sinkhole risk in Crawford 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: 8%
At or near the surface: 0%
Buried under cover: 8%

What to do about a house in Crawford County

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

That works out to roughly 56 of Crawford County's 714 square miles on soluble rock. With about 16,378 residents (23 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 390 map points about 1.4 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Crawford County

The nearest county rated sinkhole country is Knox County, NE, about 134 miles west. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Ida County, IA 25 mi north · 0% at surface
Shelby County, IA 25 mi south · 0% at surface
Carroll County, IA 27 mi east · 0% at surface
Sac County, IA 28 mi northeast · 0% at surface
Monona County, IA 29 mi west · 0% at surface
Harrison County, IA 33 mi southwest · 0% at surface

Which formation it is

The largest mapped soluble unit here is the Marmaton Group (shale), Middle Pennsylvanian-Des Moines Series in age, covering about 8% of the county.

Against the rest of Iowa

Crawford County ranks 34 of 99 in Iowa for soluble rock at the surface, and sits above 0% of US counties on that measure.