Sinkhole risk in Jackson County, MO: Sinkhole country

Sinkhole country

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

On soluble rock: 74%
At or near the surface: 71%
Buried under cover: 2%

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 446 of Jackson County's 605 square miles on soluble rock, 431 of them with the rock at or near the surface. With about 727,362 residents (1,203 per square mile), most of the county is built up, so a mapped unit is likely to sit under somebody's street. The figures come from 331 map points about 1.4 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 Jackson County

The closest county with no soluble rock mapped is Putnam County, MO, about 124 miles northeast. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Clay County, MO 22 mi north · 0% at surface
Wyandotte County, KS 24 mi west · 7% at surface
Cass County, MO 25 mi south · 72% at surface
Johnson County, KS 27 mi west · 67% at surface
Ray County, MO 28 mi northeast · 0% at surface
Lafayette County, MO 29 mi east · 32% at surface

The rock underneath

The largest mapped soluble unit here is the Kansas City Group (limestone), Late Pennsylvanian-Upper Series-Missourian Stage in age, covering about 64% of the county. Next is the Marmaton Group at 10%.

Against the rest of Missouri

Jackson County ranks 50 of 115 in Missouri for soluble rock at the surface, and sits above 93% of US counties on that measure.