Sinkhole risk in Henrico County, VA: 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: 7%
At or near the surface: 7%
Buried under cover: 0%

What to do about a house in Henrico County

Sinkholes are uncommon here; watch for new depressions after heavy rain or leaking pipes.

That works out to roughly 17 of Henrico County's 234 square miles on soluble rock, 17 of them with the rock at or near the surface. With about 338,696 residents (1,449 per square mile), most of the county is built up, so a mapped unit is likely to sit under somebody's street. The figures come from 397 map points about 0.8 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: how these percentages are measured, and the warning signs that apply anywhere.

Counties around Henrico County

The nearest county rated sinkhole country is Hertford County, NC, about 76 miles south. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Hopewell city, VA 10 mi south · 14% at surface
Richmond city, VA 12 mi northwest · 9% at surface
Colonial Heights city, VA 13 mi southwest · 12% at surface
Charles City County, VA 15 mi east · 5% at surface
Chesterfield County, VA 16 mi west · 2% at surface
Petersburg city, VA 17 mi south · 17% at surface

What Henrico County is built on

The largest mapped soluble unit here is the Chesapeake Group (sand), Tertiary in age, covering about 7% of the county. Next is the Lower Tertiary Deposits at under 1%.

Against the rest of Virginia

Henrico County ranks 61 of 133 in Virginia for soluble rock at the surface, and sits above 65% of US counties on that measure.