Sinkhole risk in Adams County, PA: 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: 6%
At or near the surface: 6%
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 30 of Adams County's 519 square miles on soluble rock, 30 of them with the rock at or near the surface. With about 107,914 residents (208 per square mile), homes are spread across towns and farmland, and a mapped unit may or may not reach the developed parts. The figures come from 318 map points about 1.3 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 Adams County

The nearest county rated sinkhole country is Washington County, MD, about 37 miles southwest, close enough that the same rock may run under the county line. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Cumberland County, PA 21 mi north · 48% at surface
Carroll County, MD 24 mi southeast · 2% at surface
York County, PA 26 mi east · 10% at surface
Franklin County, PA 27 mi west · 44% at surface
Frederick County, MD 29 mi south · 13% at surface
Perry County, PA 37 mi north · 34% at surface

Which formation it is

The largest mapped soluble unit here is the Conestoga Formation (limestone), Ordovician and Cambrian in age, covering about 2% of the county. Next is the Kinzers Formation at 2%.

Against the rest of Pennsylvania

Adams County ranks 37 of 67 in Pennsylvania for soluble rock at the surface, and sits above 64% of US counties on that measure.