SinkholeOdds

Sinkhole risk in Herkimer County, NY: 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
18%
At or near the surface
0%
Buried under cover
18%

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 247 of Herkimer County's 1,411 square miles on soluble rock. With about 59,585 residents (42 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 251 map points about 2.4 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why gypsum and salt move faster than limestone, and why the 18% under cover still counts.

Counties around Herkimer County

The nearest county rated sinkhole country is Union County, PA, about 213 miles southwest. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

The rock underneath

The largest mapped soluble unit here is the Helderberg Group (limestone), Lower Devonian in age, covering about 4% of the county. Next is the Onondaga Limestone at 4%.

The county also lies over the Michigan Basin; Ohio Basin; Appalachian Basin, a deep salt or gypsum basin. Deep beds rarely cause surface collapse on their own, but wells and mining into them have.

Against the rest of New York

Herkimer County ranks 25 of 62 in New York for soluble rock at the surface, and sits above 0% of US counties on that measure.