Sinkhole risk in Madison 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: 1%
At or near the surface: 1%
Buried under cover: 0%

What this means before you buy

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

That works out to roughly 4 of Madison County's 321 square miles on soluble rock, 4 of them with the rock at or near the surface. With about 14,252 residents (44 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 246 map points about 1.1 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 Madison County

The nearest county rated sinkhole country is Harrisonburg city, VA, about 32 miles west, close enough that the same rock may run under the county line. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Greene County, VA 13 mi southwest · 0% at surface
Culpeper County, VA 18 mi east · under 1% at surface
Orange County, VA 18 mi southeast · 4% at surface
Page County, VA 19 mi northwest · 37% at surface
Rappahannock County, VA 20 mi north · 0% at surface
Charlottesville city, VA 28 mi southwest · 0% at surface

The rock underneath

The largest mapped soluble unit here is the Newark Supergroup; Conglomerate, mixed clasts (conglomerate), Triassic in age, covering about under 1% of the county. Next is the Marble at under 1%.

Against the rest of Virginia

Madison County ranks 82 of 133 in Virginia for soluble rock at the surface, and sits above 56% of US counties on that measure.