Sinkhole risk in Logan 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: 89%
At or near the surface: 0%
Buried under cover: 89%

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 408 of Logan County's 459 square miles on soluble rock. With about 46,085 residents (101 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 326 map points about 1.2 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why the 89% under cover still counts, and how these percentages are measured.

Counties around Logan County

The nearest county rated sinkhole country is Monroe County, MI, about 107 miles north. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Champaign County, OH 18 mi south · 0% at surface
Hardin County, OH 20 mi north · 0% at surface
Union County, OH 22 mi east · 0% at surface
Shelby County, OH 23 mi west · 0% at surface
Auglaize County, OH 27 mi northwest · 1% at surface
Allen County, OH 32 mi northwest · 0% at surface

The rock underneath

The largest mapped soluble unit here is the Salina Group (dolostone (dolomite)), Silurian in age, covering about 41% of the county. Next is the Tymochtee and Greenfield Formations, Undivided at 23%.

Against the rest of Ohio

Logan County ranks 48 of 88 in Ohio for soluble rock at the surface, and sits above 0% of US counties on that measure.