Sinkhole risk in Sheridan County, NE: 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: 2%
At or near the surface: 2%
Buried under cover: 0%

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 39 of Sheridan County's 2,440 square miles on soluble rock, 39 of them with the rock at or near the surface. With about 4,927 residents (2 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 371 map points about 2.6 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Sheridan County

The nearest county rated sinkhole country is Dawes County, NE, about 41 miles west. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Dawes County, NE 41 mi west · 33% at surface
Box Butte County, NE 42 mi southwest · 0% at surface
Grant County, NE 52 mi southeast · 0% at surface
Oglala Lakota County, SD 58 mi north · 4% at surface
Bennett County, SD 58 mi northeast · 0% at surface
Garden County, NE 61 mi south · 0% at surface

What Sheridan County is built on

The largest mapped soluble unit here is the Niobrara Formation (limestone), Late Cretaceous in age, covering about 1% of the county. Next is the Carlile Shale at under 1%.

The county also lies over the Northern Denver Basin, a deep salt or gypsum basin. Deep beds rarely cause surface collapse on their own, but wells and mining into them have.

Against the rest of Nebraska

Sheridan County ranks 30 of 93 in Nebraska for soluble rock at the surface, and sits above 57% of US counties on that measure.