Sinkhole risk in Cass County, MO: Sinkhole country

Sinkhole country

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

On soluble rock: 72%
At or near the surface: 72%
Buried under cover: 0%

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 500 of Cass County's 697 square miles on soluble rock, 500 of them with the rock at or near the surface. With about 113,873 residents (163 per square mile), homes are spread across towns and farmland, and a mapped unit may or may not reach the developed parts. The figures come from 351 map points about 1.4 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: the signs to look for and how an inspection works, and how these percentages are measured.

Counties around Cass County

The closest county with no soluble rock mapped is Nemaha County, NE, about 144 miles northwest. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Jackson County, MO 25 mi north · 71% at surface
Miami County, KS 26 mi west · 87% at surface
Bates County, MO 27 mi south · 45% at surface
Johnson County, MO 30 mi east · 50% at surface
Johnson County, KS 30 mi northwest · 67% at surface
Henry County, MO 35 mi southeast · 18% at surface

Which formation it is

The largest mapped soluble unit here is the Kansas City Group (limestone), Late Pennsylvanian-Upper Series-Missourian Stage in age, covering about 39% of the county. Next is the Marmaton Group at 33%.

Against the rest of Missouri

Cass County ranks 49 of 115 in Missouri for soluble rock at the surface, and sits above 93% of US counties on that measure.