Sinkhole risk in Benton County, MO: Sinkhole country

Sinkhole country

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

On soluble rock: 89%
At or near the surface: 89%
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 626 of Benton County's 704 square miles on soluble rock, 626 of them with the rock at or near the surface. With about 20,614 residents (29 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 371 map points about 1.4 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Benton County

The closest county with no soluble rock mapped is Putnam County, MO, about 151 miles north. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Morgan County, MO 24 mi east · 100% at surface
Hickory County, MO 25 mi south · 92% at surface
Henry County, MO 28 mi west · 18% at surface
Pettis County, MO 29 mi north · 71% at surface
St. Clair County, MO 32 mi southwest · 43% at surface
Camden County, MO 34 mi southeast · 100% at surface

Which formation it is

The largest mapped soluble unit here is the Smithville Dolomite, Powell Dolomite, Cotter Dolomite, Jefferson City Dolomite (dolostone (dolomite)), Early Ordovician-Ibexian Series in age, covering about 48% of the county. Next is the Roubidoux Formation at 18%.

Against the rest of Missouri

Benton County ranks 41 of 115 in Missouri for soluble rock at the surface, and sits above 96% of US counties on that measure.