Sinkhole risk in Hall County, TX: Sinkhole country

Sinkhole country

Fast-dissolving gypsum or salt beds under a large part of the county.

On soluble rock: 69%
At or near the surface: 69%
Buried under cover: 0%

The next step for one property

Get a sinkhole or geotechnical inspection before buying, building or adding weight to a foundation.

That works out to roughly 607 of Hall County's 883 square miles on soluble rock, 607 of them with the rock at or near the surface. With about 2,828 residents (3 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 396 map points about 1.5 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Hall County

The closest county with no soluble rock mapped is Tillman County, OK, about 94 miles east. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Childress County, TX 22 mi east · 81% at surface
Motley County, TX 30 mi southwest · 55% at surface
Cottle County, TX 30 mi southeast · 79% at surface
Briscoe County, TX 36 mi west · 42% at surface
Donley County, TX 37 mi north · 28% at surface
Collingsworth County, TX 39 mi northeast · 59% at surface

What Hall County is built on

The largest mapped soluble unit here is the Whitehorse Group, undivided (sandstone), Permian; Guadalupe Series in age, covering about 62% of the county. Next is the Quartermaster Formation at 4%.

69% of the county sits on gypsum or salt, which dissolves in years rather than millennia. That share matters more than its size suggests.

The county also lies over the Permian Basin, Anadarko Basin,Dalhart Basin, Palo Duro 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 Texas

Hall County ranks 24 of 254 in Texas for soluble rock at the surface, and sits above 92% of US counties on that measure.