Sinkhole risk in Adair County, OK: Sinkhole country

Sinkhole country

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

On soluble rock: 79%
At or near the surface: 79%
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 453 of Adair County's 574 square miles on soluble rock, 453 of them with the rock at or near the surface. With about 19,821 residents (35 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 348 map points about 1.3 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 Adair County

The closest county with no soluble rock mapped is Crawford County, AR, about 32 miles southeast. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Cherokee County, OK 19 mi west · 66% at surface
Washington County, AR 25 mi east · 29% at surface
Sequoyah County, OK 28 mi south · 3% at surface
Crawford County, AR 32 mi southeast · 0% at surface
Delaware County, OK 35 mi north · 94% at surface
Benton County, AR 38 mi northeast · 93% at surface

The rock underneath

The largest mapped soluble unit here is the Keokuk and Reeds Spring Formations and St. Joe Group (chert), Early Mississippian in age, covering about 62% of the county. Next is the Bloyd and Hale Formations at 8%.

Against the rest of Oklahoma

Adair County ranks 2 of 77 in Oklahoma for soluble rock at the surface, and sits above 94% of US counties on that measure.