Sinkhole risk in Craig County, VA: Pockets of it

Pockets of it

Soluble rock at the surface or under thin cover in part of the county.

On soluble rock: 34%
At or near the surface: 34%
Buried under cover: 0%

What this means before you buy

Check the parcel against your state survey sinkhole map, and ask for an inspection if cracks, depressions or sticking doors show up.

That works out to roughly 110 of Craig County's 328 square miles on soluble rock, 110 of them with the rock at or near the surface. With about 4,829 residents (15 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 533 map points about 0.8 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: the signs to look for and how an inspection works, and how these percentages are measured.

Counties around Craig County

The nearest county rated sinkhole country is Salem city, VA, about 16 miles southeast, close enough that the same rock may run under the county line. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Roanoke County, VA 10 mi south · 33% at surface
Salem city, VA 16 mi southeast · 100% at surface
Monroe County, WV 18 mi west · 69% at surface
Roanoke city, VA 20 mi southeast · 98% at surface
Montgomery County, VA 22 mi southwest · 64% at surface
Botetourt County, VA 25 mi east · 49% at surface

Which formation it is

The largest mapped soluble unit here is the Lower Devonian and Silurian Formations Undivided (sandstone), Silurian-Devonian in age, covering about 11% of the county. Next is the Ridgeley Sandstone, Helderberg and Cayugan Groups at 10%.

Against the rest of Virginia

Craig County ranks 35 of 133 in Virginia for soluble rock at the surface, and sits above 81% of US counties on that measure.