Sinkhole risk in Surry 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: 12%
At or near the surface: 12%
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 66 of Surry County's 533 square miles on soluble rock, 66 of them with the rock at or near the surface. With about 71,547 residents (134 per square mile), homes are spread across towns and farmland, and a mapped unit may or may not reach the developed parts. The figures come from 325 map points about 1.3 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 Surry County

The nearest county rated sinkhole country is Wythe County, VA, about 40 miles northwest. None of the 6 closest counties land in the same band, so Surry County stands out from its surroundings.

Yadkin County, NC 18 mi south · 15% at surface
Galax city, VA 21 mi northwest · 0% at surface
Carroll County, VA 22 mi north · under 1% at surface
Stokes County, NC 23 mi east · 41% at surface
Alleghany County, NC 25 mi west · 0% at surface
Patrick County, VA 28 mi northeast · 0% at surface

Which formation it is

The largest mapped soluble unit here is the Metagraywacke and Muscovite-Biotite Schist (metasedimentary rock), Cambrian/Late Proterozoic in age, covering about 12% of the county.

Against the rest of North Carolina

Surry County ranks 38 of 100 in North Carolina for soluble rock at the surface, and sits above 69% of US counties on that measure.