SinkholeOdds

Sinkhole risk in Jefferson 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
50%
At or near the surface
0%
Buried under cover
50%

What to do about a house in Jefferson County

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

That works out to roughly 628 of Jefferson County's 1,268 square miles on soluble rock. With about 113,140 residents (89 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 600 map points about 1.5 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why the 50% under cover still counts, and how these percentages are measured.

Counties around Jefferson County

The nearest county rated sinkhole country is Union County, PA, about 216 miles south. 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 Trenton Group (shale), Middle Ordovician in age, covering about 23% of the county. Next is the Black River Group at 18%.

Against the rest of New York

Jefferson County ranks 26 of 62 in New York for soluble rock at the surface, and sits above 0% of US counties on that measure.