Sinkhole risk in Clay County, NE: Pockets of it

Pockets of it

Soluble rock at the surface or under thin cover in part of the county.

On soluble rock: 69%
At or near the surface: 60%
Buried under cover: 10%

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 397 of Clay County's 572 square miles on soluble rock, 342 of them with the rock at or near the surface. With about 6,103 residents (11 per square mile), much of the land is open, and the mapped rock may sit far from where people actually live. The figures come from 414 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 10% under cover still counts, and the signs to look for and how an inspection works.

Counties around Clay County

The nearest county rated sinkhole country is Kearney County, NE, about 47 miles west. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Adams County, NE 24 mi west · 79% at surface
Fillmore County, NE 24 mi east · 0% at surface
Nuckolls County, NE 24 mi south · 52% at surface
Hamilton County, NE 24 mi north · 80% at surface
Webster County, NE 33 mi southwest · 78% at surface
Hall County, NE 33 mi northwest · 33% at surface

The rock underneath

The largest mapped soluble unit here is the Niobrara Formation (limestone), Late Cretaceous in age, covering about 69% of the county.

Against the rest of Nebraska

Clay County ranks 7 of 93 in Nebraska for soluble rock at the surface, and sits above 90% of US counties on that measure.