Sinkhole risk in Rockbridge County, VA: Sinkhole country

Sinkhole country

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

On soluble rock: 57%
At or near the surface: 57%
Buried under cover: 0%

What this means before you buy

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

That works out to roughly 341 of Rockbridge County's 597 square miles on soluble rock, 341 of them with the rock at or near the surface. With about 22,368 residents (37 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 552 map points about 1.0 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Rockbridge County

The closest county with no soluble rock mapped is Amherst County, VA, about 20 miles southeast. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Lexington city, VA 2 mi south · 100% at surface
Buena Vista city, VA 8 mi southeast · 75% at surface
Amherst County, VA 20 mi southeast · under 1% at surface
Bath County, VA 23 mi northwest · 24% at surface
Botetourt County, VA 26 mi southwest · 49% at surface
Covington city, VA 29 mi west · 26% at surface

Which formation it is

The largest mapped soluble unit here is the Beekmantown Group (dolostone (dolomite)), Ordovician in age, covering about 15% of the county. Next is the Edinburg Formation, Lincolnshire and New Market Limestones at 12%.

Against the rest of Virginia

Rockbridge County ranks 20 of 133 in Virginia for soluble rock at the surface, and sits above 89% of US counties on that measure.