Sinkhole risk in Boone County, AR: Sinkhole country

Sinkhole country

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

On soluble rock: 83%
At or near the surface: 83%
Buried under cover: 0%

What to do about a house in Boone County

Get a sinkhole or geotechnical inspection before buying, building or adding weight to a foundation.

That works out to roughly 487 of Boone County's 590 square miles on soluble rock, 487 of them with the rock at or near the surface. With about 38,636 residents (66 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 365 map points about 1.3 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Boone County

The closest county with no soluble rock mapped is Johnson County, AR, about 55 miles southwest. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Marion County, AR 22 mi east · 94% at surface
Taney County, MO 24 mi north · 100% at surface
Carroll County, AR 26 mi west · 81% at surface
Newton County, AR 28 mi south · 24% at surface
Searcy County, AR 35 mi southeast · 46% at surface
Stone County, MO 37 mi northwest · 100% at surface

Which formation it is

The largest mapped soluble unit here is the Boone Formation (limestone), Early Mississippian- Meramecian to Osagean in age, covering about 49% of the county. Next is the Cotter and Jefferson City Dolomites at 17%.

Against the rest of Arkansas

Boone County ranks 7 of 75 in Arkansas for soluble rock at the surface, and sits above 95% of US counties on that measure.