Sinkhole risk in Linn County, KS: Sinkhole country

Sinkhole country

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

On soluble rock: 69%
At or near the surface: 69%
Buried under cover: 0%

What to do about a house in Linn County

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

That works out to roughly 409 of Linn County's 594 square miles on soluble rock, 409 of them with the rock at or near the surface. With about 9,841 residents (17 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 389 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 Linn County

The closest county with no soluble rock mapped is Nemaha County, NE, about 159 miles north. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Miami County, KS 24 mi north · 87% at surface
Anderson County, KS 24 mi west · 55% at surface
Bourbon County, KS 25 mi south · 68% at surface
Bates County, MO 28 mi east · 45% at surface
Franklin County, KS 33 mi northwest · 33% at surface
Allen County, KS 34 mi southwest · 90% at surface

The rock underneath

The largest mapped soluble unit here is the Kansas City Group (limestone), Middle Pennsylvanian- Missourian in age, covering about 54% of the county. Next is the Marmaton Group at 15%.

Against the rest of Kansas

Linn County ranks 14 of 105 in Kansas for soluble rock at the surface, and sits above 92% of US counties on that measure.