Sinkhole risk in Rush 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: 98%
At or near the surface: 0%
Buried under cover: 98%

What to do about a house in Rush County

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

That works out to roughly 399 of Rush County's 408 square miles on soluble rock. With about 16,759 residents (41 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 1.0 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why the 98% under cover still counts, and how these percentages are measured.

Counties around Rush County

The nearest county rated sinkhole country is Monroe County, IN, about 65 miles southwest. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Fayette County, IN 15 mi east · 0% at surface
Shelby County, IN 19 mi west · 0% at surface
Hancock County, IN 21 mi northwest · 0% at surface
Henry County, IN 22 mi north · 0% at surface
Decatur County, IN 22 mi south · 2% at surface
Franklin County, IN 26 mi southeast · 2% at surface

The rock underneath

The largest mapped soluble unit here is the Louisville Limestone through Brassfield Limestone (limestone), Silurian in age, covering about 51% of the county. Next is the Muscatatuck Group at 34%.

Against the rest of Indiana

Rush County ranks 76 of 92 in Indiana for soluble rock at the surface, and sits above 0% of US counties on that measure.