Sinkhole risk in Racine County, WI: 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 323 of Racine County's 333 square miles on soluble rock. With about 198,651 residents (597 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 316 map points about 1.0 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 Racine County

The nearest county rated sinkhole country is Muskegon County, MI, about 82 miles northeast. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Milwaukee County, WI 10 mi northwest · 0% at surface
Kenosha County, WI 14 mi south · 0% at surface
Waukesha County, WI 32 mi northwest · 0% at surface
Walworth County, WI 40 mi west · 0% at surface
Lake County, IL 41 mi south · 0% at surface
McHenry County, IL 47 mi southwest · 0% at surface

Which formation it is

The largest mapped soluble unit here is the Silurian, undivided (dolostone (dolomite)), Silurian in age, covering about 96% of the county. Next is the Maquoketa Formation at 1%.

Against the rest of Wisconsin

Racine County ranks 58 of 72 in Wisconsin for soluble rock at the surface, and sits above 0% of US counties on that measure.