Sinkhole risk in Cumberland County, PA: Pockets of it

Pockets of it

Soluble rock at the surface or under thin cover in part of the county.

On soluble rock: 48%
At or near the surface: 48%
Buried under cover: 0%

What this means before you buy

Check the parcel against your state survey sinkhole map, and ask for an inspection if cracks, depressions or sticking doors show up.

That works out to roughly 260 of Cumberland County's 545 square miles on soluble rock, 260 of them with the rock at or near the surface. With about 275,516 residents (505 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 525 map points about 1.0 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: the signs to look for and how an inspection works, and how these percentages are measured.

Counties around Cumberland County

The nearest county rated sinkhole country is Washington County, MD, about 49 miles southwest. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Perry County, PA 16 mi north · 34% at surface
Adams County, PA 21 mi south · 6% at surface
Juniata County, PA 26 mi north · 45% at surface
Franklin County, PA 29 mi southwest · 44% at surface
Dauphin County, PA 30 mi northeast · 8% at surface
York County, PA 33 mi southeast · 10% at surface

The rock underneath

The largest mapped soluble unit here is the Rockdale Run Formation (limestone), Ordovician in age, covering about 9% of the county. Next is the Elbrook Formation at 8%.

Against the rest of Pennsylvania

Cumberland County ranks 2 of 67 in Pennsylvania for soluble rock at the surface, and sits above 87% of US counties on that measure.