SinkholeOdds

Sinkhole risk in Harrison County, MO: Mostly deep or small

Mostly deep or small

Some soluble rock, mostly deeply buried or in a small share of the county.

On soluble rock
78%
At or near the surface
0%
Buried under cover
78%

What this means before you buy

Sinkholes are uncommon here; watch for new depressions after heavy rain or leaking pipes.

That works out to roughly 564 of Harrison County's 723 square miles on soluble rock. With about 8,186 residents (11 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 379 map points about 1.4 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why gypsum and salt move faster than limestone, and why the 78% under cover still counts.

Counties around Harrison County

The nearest county rated sinkhole country is Jackson County, MO, about 94 miles south. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

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 73% of the county. Next is the Lansing Group at 5%.

The county also lies over the Forest City Basin, a deep salt or gypsum basin. Deep beds rarely cause surface collapse on their own, but wells and mining into them have.

Against the rest of Missouri

Harrison County ranks 92 of 115 in Missouri for soluble rock at the surface, and sits above 0% of US counties on that measure.