Sinkhole risk in Hamilton 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: 2%
Buried under cover: 98%

What to do about a house in Hamilton County

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 404 of Hamilton County's 405 square miles on soluble rock, 6 of them with the rock at or near the surface. With about 837,359 residents (2,065 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 264 map points about 1.2 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why the 98% under cover still counts, and the signs to look for and how an inspection works.

Counties around Hamilton County

The nearest county rated sinkhole country is Kenton County, KY, about 18 miles south, 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.

Butler County, OH 17 mi north · 0% at surface
Kenton County, KY 18 mi south · 59% at surface
Campbell County, KY 19 mi southeast · 26% at surface
Boone County, KY 19 mi southwest · 16% at surface
Clermont County, OH 23 mi southeast · 0% at surface
Dearborn County, IN 23 mi west · 10% at surface

What Hamilton County is built on

The largest mapped soluble unit here is the Grant Lake and Fairview Formations, Miamitown Shale, Undivided (limestone), Ordovician in age, covering about 44% of the county. Next is the Kope Formation at 27%.

Against the rest of Ohio

Hamilton County ranks 8 of 88 in Ohio for soluble rock at the surface, and sits above 56% of US counties on that measure.