Sinkhole risk in Sibley 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: 2%
At or near the surface: 0%
Buried under cover: 2%

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 9 of Sibley County's 589 square miles on soluble rock. With about 15,194 residents (26 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 309 map points about 1.4 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: how these percentages are measured, and the warning signs that apply anywhere.

Counties around Sibley County

The nearest county rated sinkhole country is Vernon County, WI, about 182 miles east. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Nicollet County, MN 15 mi south · 0% at surface
McLeod County, MN 17 mi north · 0% at surface
Carver County, MN 27 mi northeast · 0% at surface
Le Sueur County, MN 28 mi southeast · 0% at surface
Brown County, MN 34 mi southwest · 0% at surface
Scott County, MN 35 mi east · 0% at surface

Which formation it is

The largest mapped soluble unit here is the Lower Ordovician rocks, undivided (dolostone (dolomite)), Lower Ordovician in age, covering about 2% of the county.

Against the rest of Minnesota

Sibley County ranks 74 of 87 in Minnesota for soluble rock at the surface, and sits above 0% of US counties on that measure.