Sinkhole risk in Delaware 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: 36%
At or near the surface: 0%
Buried under cover: 36%

What to do about a house in Delaware County

Sinkholes are uncommon here; watch for new depressions after heavy rain or leaking pipes.

That works out to roughly 159 of Delaware County's 443 square miles on soluble rock. With about 237,966 residents (537 per square mile), most of the county is built up, so a mapped unit is likely to sit under somebody's street. The figures come from 316 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 36% under cover still counts, and how these percentages are measured.

Counties around Delaware County

The nearest county rated sinkhole country is Monroe County, MI, about 116 miles north. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Union County, OH 19 mi west · 0% at surface
Morrow County, OH 20 mi northeast · 0% at surface
Franklin County, OH 21 mi south · 0% at surface
Marion County, OH 23 mi north · 0% at surface
Licking County, OH 31 mi southeast · 0% at surface
Knox County, OH 32 mi east · 0% at surface

The rock underneath

The largest mapped soluble unit here is the Salina Group (dolostone (dolomite)), Silurian in age, covering about 13% of the county. Next is the Columbus Limestone at 10%.

Against the rest of Ohio

Delaware County ranks 28 of 88 in Ohio for soluble rock at the surface, and sits above 0% of US counties on that measure.