Sinkhole risk in Brown County, OH: Pockets of it

Pockets of it

Soluble rock at the surface or under thin cover in part of the county.

On soluble rock: 100%
At or near the surface: 9%
Buried under cover: 91%

The next step for one property

Check the parcel against your state survey sinkhole map, and ask for an inspection if cracks, depressions or sticking doors show up.

That works out to roughly 487 of Brown County's 490 square miles on soluble rock, 43 of them with the rock at or near the surface. With about 44,292 residents (90 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 577 map points about 0.9 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why the 91% under cover still counts, and the signs to look for and how an inspection works.

Counties around Brown County

The nearest county rated sinkhole country is Mason County, KY, about 23 miles south, close enough that the same rock may run under the county line. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Clermont County, OH 17 mi northwest · 0% at surface
Bracken County, KY 22 mi southwest · 33% at surface
Adams County, OH 22 mi east · 35% at surface
Highland County, OH 23 mi northeast · 3% at surface
Mason County, KY 23 mi south · 76% at surface
Campbell County, KY 28 mi west · 26% at surface

The rock underneath

The largest mapped soluble unit here is the Grant Lake Limestone and Fairview Formation, Undivided (limestone), Ordovician in age, covering about 37% of the county. Next is the Preacherville Member of the Drakes Formation, Waynesville and Arnheim Formation, Undivided at 35%.

Against the rest of Ohio

Brown County ranks 5 of 88 in Ohio for soluble rock at the surface, and sits above 67% of US counties on that measure.