Sinkhole risk in Mower County, MN: 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: 91%
At or near the surface: 0%
Buried under cover: 91%

The next step for one property

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

That works out to roughly 646 of Mower County's 711 square miles on soluble rock. With about 40,900 residents (58 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 390 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 the 91% under cover still counts, and how these percentages are measured.

Counties around Mower County

The nearest county rated sinkhole country is Clayton County, IA, about 92 miles southeast. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Mitchell County, IA 22 mi south · 0% at surface
Dodge County, MN 25 mi north · 0% at surface
Olmsted County, MN 29 mi northeast · 6% at surface
Freeborn County, MN 30 mi west · 0% at surface
Howard County, IA 30 mi southeast · 5% at surface
Worth County, IA 32 mi southwest · 0% at surface

The rock underneath

The largest mapped soluble unit here is the Bassett Member of the Little Cedar Formation (Cedar Valley Group) and Pinicon Ridge and Spillville Formations (Wapsipinicon Group) (dolostone (dolomite)), Devonian in age, covering about 49% of the county. Next is the Lithograph City Formation, Coralville Formation and Hinckle and Eagle City Members of the Little Cedar Formation (Cedar Valley Group), undivided at 32%.

Against the rest of Minnesota

Mower County ranks 54 of 87 in Minnesota for soluble rock at the surface, and sits above 0% of US counties on that measure.