Sinkhole risk in Madison County, IN: 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: 100%
At or near the surface: 0%
Buried under cover: 100%

What to do about a house in Madison County

Sinkholes are uncommon here; watch for new depressions after heavy rain or leaking pipes.

That works out to roughly 452 of Madison County's 452 square miles on soluble rock. With about 134,222 residents (297 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 400 map points about 1.1 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Madison County

The nearest county rated sinkhole country is Monroe County, IN, about 81 miles southwest. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Delaware County, IN 18 mi east · 0% at surface
Hamilton County, IN 18 mi southwest · 0% at surface
Tipton County, IN 20 mi northwest · 0% at surface
Henry County, IN 24 mi southeast · 0% at surface
Hancock County, IN 24 mi south · 0% at surface
Grant County, IN 24 mi north · 0% at surface

The rock underneath

The largest mapped soluble unit here is the Wabash Formation (limestone), Silurian in age, covering about 68% of the county. Next is the Pleasant Mills Formation at 19%.

Against the rest of Indiana

Madison County ranks 65 of 92 in Indiana for soluble rock at the surface, and sits above 0% of US counties on that measure.