Sinkhole risk in Little River County, AR: 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: 4%
At or near the surface: 4%
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 21 of Little River County's 531 square miles on soluble rock, 21 of them with the rock at or near the surface. With about 11,626 residents (22 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 544 map points about 1.0 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why gypsum and salt move faster than limestone, and how these percentages are measured.

Counties around Little River County

The nearest county rated sinkhole country is Adair County, OK, about 154 miles north. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Sevier County, AR 20 mi north · 26% at surface
Bowie County, TX 21 mi southwest · 24% at surface
Howard County, AR 30 mi northeast · 23% at surface
Hempstead County, AR 33 mi east · 43% at surface
Miller County, AR 34 mi southeast · 0% at surface
McCurtain County, OK 42 mi northwest · 6% at surface

What Little River County is built on

The largest mapped soluble unit here is the Ozan Formation (mixed clastic/carbonate), Late Cretaceous in age, covering about 1% of the county. Next is the Marlbrook Marl at 1%.

The county also lies over the Gulf Coast salt domes, 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 Arkansas

Little River County ranks 32 of 75 in Arkansas for soluble rock at the surface, and sits above 61% of US counties on that measure.