Sinkhole risk in Green Lake 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: 27%
At or near the surface: 0%
Buried under cover: 27%

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 94 of Green Lake County's 350 square miles on soluble rock. With about 19,370 residents (55 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 353 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 27% under cover still counts, and how these percentages are measured.

Counties around Green Lake County

The nearest county rated sinkhole country is Iowa County, WI, about 79 miles southwest. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Marquette County, WI 22 mi west · 0% at surface
Fond du Lac County, WI 24 mi east · 0% at surface
Winnebago County, WI 26 mi northeast · under 1% at surface
Waushara County, WI 27 mi northwest · 0% at surface
Dodge County, WI 28 mi southeast · 0% at surface
Columbia County, WI 28 mi southwest · under 1% at surface

The rock underneath

The largest mapped soluble unit here is the Prairie du Chien Group (shale), Lower Ordovician in age, covering about 16% of the county. Next is the Sinnipee Group at 7%.

Against the rest of Wisconsin

Green Lake County ranks 39 of 72 in Wisconsin for soluble rock at the surface, and sits above 0% of US counties on that measure.