Sinkhole risk in Calhoun County, IA: No soluble rock mapped

No soluble rock mapped

No soluble bedrock mapped.

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

The next step for one property

No soluble bedrock is mapped here, so natural sinkholes are unlikely. Collapses from broken pipes or old mines are a separate risk.

Across 570 square miles, under one square mile of Calhoun County maps onto soluble rock. With about 9,711 residents (17 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 340 map points about 1.3 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: how these percentages are measured, and the warning signs that apply anywhere.

Counties around Calhoun County

The nearest county rated sinkhole country is Knox County, NE, about 166 miles west. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Sac County, IA 24 mi west · 0% at surface
Webster County, IA 24 mi east · 0% at surface
Pocahontas County, IA 24 mi north · 0% at surface
Carroll County, IA 27 mi southwest · 0% at surface
Greene County, IA 27 mi southeast · 0% at surface
Buena Vista County, IA 35 mi northwest · 0% at surface

Against the rest of Iowa

Calhoun County ranks 25 of 99 in Iowa for soluble rock at the surface, and sits above 0% of US counties on that measure.