Sinkhole risk in Camden County, NJ: 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%

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 13 of Camden County's 221 square miles on soluble rock, 13 of them with the rock at or near the surface. With about 533,988 residents (2,412 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 416 map points about 0.7 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 Camden County

The nearest county rated sinkhole country is Union County, PA, about 136 miles northwest. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Gloucester County, NJ 11 mi southwest · 9% at surface
Burlington County, NJ 17 mi east · 4% at surface
Philadelphia County, PA 17 mi northwest · 0% at surface
Delaware County, PA 25 mi west · 0% at surface
Salem County, NJ 26 mi southwest · 15% at surface
Atlantic County, NJ 29 mi southeast · 0% at surface

What Camden County is built on

The largest mapped soluble unit here is the Mt. Laurel Formation (sand), Upper Cretaceous, upper Campanian in age, covering about 5% of the county. Next is the Vincentown Formation at under 1%.

Against the rest of New Jersey

Camden County ranks 5 of 21 in New Jersey for soluble rock at the surface, and sits above 64% of US counties on that measure.