Sinkhole risk in Kendall County, IL: 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: 45%
At or near the surface: 2%
Buried under cover: 43%

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 145 of Kendall County's 320 square miles on soluble rock, 7 of them with the rock at or near the surface. With about 143,171 residents (447 per square mile), homes are spread across towns and farmland, and a mapped unit may or may not reach the developed parts. The figures come from 385 map points about 0.9 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why the 43% under cover still counts, and how these percentages are measured.

Counties around Kendall County

The nearest county rated sinkhole country is Jo Daviess County, IL, about 106 miles northwest. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Grundy County, IL 20 mi south · 0% at surface
Kane County, IL 24 mi north · 0% at surface
Will County, IL 25 mi east · 3% at surface
DuPage County, IL 25 mi northeast · 0% at surface
DeKalb County, IL 27 mi northwest · 0% at surface
LaSalle County, IL 29 mi southwest · 0% at surface

What Kendall County is built on

The largest mapped soluble unit here is the Galena-Platteville Groups (limestone), Ordovician in age, covering about 33% of the county. Next is the Silurian at 9%.

Against the rest of Illinois

Kendall County ranks 19 of 102 in Illinois for soluble rock at the surface, and sits above 58% of US counties on that measure.