Sinkhole risk in Faribault 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: 97%
At or near the surface: 0%
Buried under cover: 97%

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 693 of Faribault County's 712 square miles on soluble rock. With about 13,886 residents (19 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.

Worth reading for this county: why the 97% under cover still counts, and how these percentages are measured.

Counties around Faribault County

The nearest county rated sinkhole country is Clayton County, IA, about 144 miles southeast. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Winnebago County, IA 23 mi southeast · 0% at surface
Blue Earth County, MN 25 mi north · 0% at surface
Waseca County, MN 30 mi northeast · 0% at surface
Freeborn County, MN 30 mi east · 0% at surface
Martin County, MN 30 mi west · 0% at surface
Kossuth County, IA 35 mi southwest · 0% at surface

What Faribault County is built on

The largest mapped soluble unit here is the Upper and Middle Ordovician rocks, undivided (limestone), Late and Middle Ordovician in age, covering about 56% of the county. Next is the Middle Ordovician rocks, undivided at 36%.

Against the rest of Minnesota

Faribault County ranks 29 of 87 in Minnesota for soluble rock at the surface, and sits above 0% of US counties on that measure.