Sinkhole risk in Richmond city, 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: 9%
At or near the surface: 9%
Buried under cover: 0%

The next step for one property

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

That works out to roughly 5 of Richmond city's 60 square miles on soluble rock, 5 of them with the rock at or near the surface. With about 233,655 residents (3,899 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 559 map points about 0.3 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: how these percentages are measured, and the warning signs that apply anywhere.

Counties around Richmond city

The nearest county rated sinkhole country is Hertford County, NC, about 85 miles south. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Henrico County, VA 12 mi southeast · 7% at surface
Chesterfield County, VA 12 mi southwest · 2% at surface
Hanover County, VA 16 mi north · 11% at surface
Colonial Heights city, VA 19 mi south · 12% at surface
Hopewell city, VA 19 mi southeast · 14% at surface
Petersburg city, VA 23 mi south · 17% at surface

What Richmond city 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 2%.

Against the rest of Virginia

Richmond city ranks 58 of 133 in Virginia for soluble rock at the surface, and sits above 67% of US counties on that measure.