Sinkhole risk in Houston County, MN: Pockets of it

Pockets of it

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

On soluble rock: 61%
At or near the surface: 28%
Buried under cover: 34%

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 338 of Houston County's 552 square miles on soluble rock, 152 of them with the rock at or near the surface. With about 18,352 residents (33 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 363 map points about 1.2 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why the 34% under cover still counts, and the signs to look for and how an inspection works.

Counties around Houston County

The nearest county rated sinkhole country is Vernon County, WI, about 34 miles east, close enough that the same rock may run under the county line. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

La Crosse County, WI 26 mi northeast · 22% at surface
Winona County, MN 26 mi northwest · 27% at surface
Allamakee County, IA 28 mi south · 25% at surface
Fillmore County, MN 30 mi west · 26% at surface
Winneshiek County, IA 31 mi southwest · 18% at surface
Vernon County, WI 34 mi east · 63% at surface

The rock underneath

The largest mapped soluble unit here is the Lower Ordovician rocks, undivided (dolostone (dolomite)), Lower Ordovician in age, covering about 56% of the county. Next is the Middle Ordovician rocks, undivided at 4%.

Against the rest of Minnesota

Houston County ranks 1 of 87 in Minnesota for soluble rock at the surface, and sits above 78% of US counties on that measure.