Sinkhole risk in Giles County, VA: Sinkhole country

Sinkhole country

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

On soluble rock: 65%
At or near the surface: 65%
Buried under cover: 0%

What to do about a house in Giles County

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

That works out to roughly 231 of Giles County's 357 square miles on soluble rock, 231 of them with the rock at or near the surface. With about 16,533 residents (46 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 508 map points about 0.8 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Giles County

The closest county with no soluble rock mapped is Floyd County, VA, about 33 miles southeast. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Radford city, VA 16 mi southeast · 84% at surface
Pulaski County, VA 18 mi south · 57% at surface
Monroe County, WV 18 mi northeast · 69% at surface
Montgomery County, VA 20 mi southeast · 64% at surface
Mercer County, WV 23 mi west · 39% at surface
Summers County, WV 25 mi north · 73% at surface

Which formation it is

The largest mapped soluble unit here is the Knox Group (dolostone (dolomite)), Cambrian-Ordovician in age, covering about 23% of the county. Next is the Lower Devonian and Silurian Formations Undivided at 21%.

Against the rest of Virginia

Giles County ranks 14 of 133 in Virginia for soluble rock at the surface, and sits above 91% of US counties on that measure.