Sinkhole risk in Swain County, NC: 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 13 of Swain County's 528 square miles on soluble rock, 13 of them with the rock at or near the surface. With about 13,945 residents (26 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 422 map points about 1.1 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: how these percentages are measured, and the warning signs that apply anywhere.

Counties around Swain County

The nearest county rated sinkhole country is Blount County, TN, about 27 miles west, close enough that the same rock may run under the county line. None of the 6 closest counties land in the same band, so Swain County stands out from its surroundings.

Sevier County, TN 15 mi north · 36% at surface
Graham County, NC 26 mi southwest · 0% at surface
Blount County, TN 27 mi west · 58% at surface
Haywood County, NC 27 mi east · under 1% at surface
Jackson County, NC 27 mi southeast · 0% at surface
Macon County, NC 29 mi south · 0% at surface

What Swain County is built on

The largest mapped soluble unit here is the Ocoee Supergroup, Great Smokey Group; Anakeesta Formation (slate), Late Proterozoic in age, covering about 2% of the county. Next is the Murphy Marble, Andrews Formation, and Nottely Quartzite, undivided at under 1%.

Against the rest of North Carolina

Swain County ranks 57 of 100 in North Carolina for soluble rock at the surface, and sits above 59% of US counties on that measure.