Sinkhole risk in Bartholomew 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: 44%
At or near the surface: 0%
Buried under cover: 44%

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 177 of Bartholomew County's 407 square miles on soluble rock. With about 84,741 residents (208 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 359 map points about 1.1 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why gypsum and salt move faster than limestone, and why the 44% under cover still counts.

Counties around Bartholomew County

The nearest county rated sinkhole country is Monroe County, IN, about 34 miles west, close enough that the same rock may run under the county line. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Brown County, IN 18 mi west · 0% at surface
Jennings County, IN 20 mi southeast · 7% at surface
Jackson County, IN 22 mi south · 2% at surface
Decatur County, IN 22 mi east · 2% at surface
Johnson County, IN 23 mi northwest · 0% at surface
Shelby County, IN 23 mi north · 0% at surface

Which formation it is

The largest mapped soluble unit here is the Muscatatuck Group (limestone), Devonian in age, covering about 42% of the county. Next is the Louisville Limestone through Brassfield Limestone at 1%.

The county also lies over the Illinois Basin, a deep salt or gypsum basin. Deep beds rarely cause surface collapse on their own, but wells and mining into them have.

Against the rest of Indiana

Bartholomew County ranks 36 of 92 in Indiana for soluble rock at the surface, and sits above 0% of US counties on that measure.