Sinkhole risk in Defiance County, OH: 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: 14%
At or near the surface: 0%
Buried under cover: 14%

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 57 of Defiance County's 411 square miles on soluble rock. With about 38,644 residents (94 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 296 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 14% under cover still counts, and how these percentages are measured.

Counties around Defiance County

The nearest county rated sinkhole country is Monroe County, MI, about 66 miles northeast. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Paulding County, OH 15 mi south · 0% at surface
Williams County, OH 18 mi north · 0% at surface
Henry County, OH 22 mi east · 0% at surface
Fulton County, OH 27 mi northeast · 0% at surface
DeKalb County, IN 27 mi west · 0% at surface
Putnam County, OH 28 mi southeast · 0% at surface

The rock underneath

The largest mapped soluble unit here is the Traverse Group (dolostone (dolomite)), Devonian in age, covering about 7% of the county. Next is the Dundee Limestone at 4%.

Against the rest of Ohio

Defiance County ranks 27 of 88 in Ohio for soluble rock at the surface, and sits above 0% of US counties on that measure.