Sinkhole risk in Red Willow 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: 16%
At or near the surface: 16%
Buried under cover: 0%

What this means before you buy

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 117 of Red Willow County's 717 square miles on soluble rock, 117 of them with the rock at or near the surface. With about 10,409 residents (15 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 400 map points about 1.3 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Red Willow County

The nearest county rated sinkhole country is Harlan County, NE, about 56 miles east. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Frontier County, NE 25 mi north · under 1% at surface
Decatur County, KS 27 mi south · 19% at surface
Furnas County, NE 30 mi east · 32% at surface
Hitchcock County, NE 30 mi west · 20% at surface
Hayes County, NE 40 mi northwest · under 1% at surface
Norton County, KS 40 mi southeast · 22% at surface

Which formation it is

The largest mapped soluble unit here is the Pierre Shale (shale), Late Cretaceous in age, covering about 9% of the county. Next is the Niobrara Formation at 7%.

9% of the county sits on gypsum or salt, which dissolves in years rather than millennia. That share matters more than its size suggests.

Against the rest of Nebraska

Red Willow County ranks 20 of 93 in Nebraska for soluble rock at the surface, and sits above 72% of US counties on that measure.