Sinkhole risk in Union 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: 53%
At or near the surface: 0%
Buried under cover: 53%

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 85 of Union County's 161 square miles on soluble rock. With about 6,884 residents (43 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 398 map points about 0.6 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Union County

The nearest county rated sinkhole country is Kenton County, KY, about 52 miles southeast. 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 14 mi west · 0% at surface
Franklin County, IN 17 mi southwest · 2% at surface
Preble County, OH 17 mi northeast · 0% at surface
Wayne County, IN 17 mi north · under 1% at surface
Butler County, OH 23 mi southeast · 0% at surface
Rush County, IN 29 mi west · 0% at surface

Which formation it is

The largest mapped soluble unit here is the Whitewater Formation (limestone), Ordovician in age, covering about 48% of the county. Next is the Louisville Limestone through Brassfield Limestone at 5%.

Against the rest of Indiana

Union County ranks 84 of 92 in Indiana for soluble rock at the surface, and sits above 0% of US counties on that measure.