Sinkhole risk in Greene County, NC: Sinkhole country

Sinkhole country

Soluble rock at or near the surface across much of the county.

On soluble rock: 82%
At or near the surface: 82%
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 220 of Greene County's 267 square miles on soluble rock, 220 of them with the rock at or near the surface. With about 20,671 residents (77 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 260 map points about 1.0 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: the signs to look for and how an inspection works, and how these percentages are measured.

Counties around Greene County

The closest county with no soluble rock mapped is Franklin County, NC, about 54 miles northwest. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Lenoir County, NC 17 mi south · 71% at surface
Pitt County, NC 19 mi northeast · 86% at surface
Wilson County, NC 20 mi northwest · 68% at surface
Wayne County, NC 20 mi southwest · 84% at surface
Edgecombe County, NC 30 mi north · 62% at surface
Jones County, NC 36 mi southeast · 92% at surface

Which formation it is

The largest mapped soluble unit here is the Yorktown Formation and Duplin Formation, Undivided (clay or mud), Tertiary in age, covering about 69% of the county. Next is the Black Creek Formation at 9%.

Against the rest of North Carolina

Greene County ranks 10 of 100 in North Carolina for soluble rock at the surface, and sits above 95% of US counties on that measure.