Sinkhole risk in Ottawa 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: 80%
At or near the surface: 0%
Buried under cover: 80%

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 203 of Ottawa County's 255 square miles on soluble rock. With about 39,692 residents (156 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 488 map points about 0.7 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Ottawa County

The nearest county rated sinkhole country is Monroe County, MI, about 35 miles northwest, close enough that the same rock may run under the county line. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Sandusky County, OH 15 mi southwest · 0% at surface
Erie County, OH 24 mi southeast · under 1% at surface
Lucas County, OH 25 mi west · 0% at surface
Seneca County, OH 30 mi south · 0% at surface
Wood County, OH 34 mi west · 0% at surface
Huron County, OH 35 mi southeast · 0% at surface

What Ottawa County is built on

The largest mapped soluble unit here is the Lockport Dolomite (dolostone (dolomite)), Silurian in age, covering about 31% of the county. Next is the Tymochtee and Greenfield Formations, Undivided at 29%.

Against the rest of Ohio

Ottawa County ranks 63 of 88 in Ohio for soluble rock at the surface, and sits above 0% of US counties on that measure.