Sinkhole risk in McDonald County, MO: Sinkhole country

Sinkhole country

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

On soluble rock: 100%
At or near the surface: 100%
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 539 of McDonald County's 539 square miles on soluble rock, 539 of them with the rock at or near the surface. With about 24,054 residents (45 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 382 map points about 1.2 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 McDonald County

The closest county with no soluble rock mapped is Crawford County, AR, about 72 miles south. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Newton County, MO 19 mi north · 99% at surface
Benton County, AR 21 mi south · 93% at surface
Barry County, MO 29 mi east · 99% at surface
Ottawa County, OK 29 mi northwest · 63% at surface
Delaware County, OK 30 mi southwest · 94% at surface
Jasper County, MO 40 mi north · 85% at surface

The rock underneath

The largest mapped soluble unit here is the Osagean Series (limestone), Early Mississippian-Osagean Series in age, covering about 85% of the county. Next is the Kinderhookian Series at 9%.

Against the rest of Missouri

McDonald County ranks 8 of 115 in Missouri for soluble rock at the surface, and sits above 99% of US counties on that measure.