Sinkhole risk in Butler County, KS: Pockets of it

Pockets of it

Soluble rock at the surface or under thin cover in part of the county.

On soluble rock: 93%
At or near the surface: 93%
Buried under cover: 0%

What this means before you buy

Check the parcel against your state survey sinkhole map, and ask for an inspection if cracks, depressions or sticking doors show up.

That works out to roughly 1,330 of Butler County's 1,430 square miles on soluble rock, 1,330 of them with the rock at or near the surface. With about 69,158 residents (48 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 400 map points about 1.9 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why gypsum and salt move faster than limestone, and the signs to look for and how an inspection works.

Counties around Butler County

The nearest county rated sinkhole country is Marion County, KS, about 43 miles north. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Greenwood County, KS 33 mi east · 55% at surface
Sedgwick County, KS 35 mi west · 16% at surface
Cowley County, KS 37 mi south · 74% at surface
Harvey County, KS 38 mi northwest · 21% at surface
Chase County, KS 39 mi north · 87% at surface
Elk County, KS 39 mi southeast · 53% at surface

Which formation it is

The largest mapped soluble unit here is the Chase Group (shale), Early Permian - Gearyan in age, covering about 76% of the county. Next is the Sumner Group at 15%.

15% of the county sits on gypsum or salt, which dissolves in years rather than millennia. That share matters more than its size suggests.

Against the rest of Kansas

Butler County ranks 1 of 105 in Kansas for soluble rock at the surface, and sits above 97% of US counties on that measure.