SinkholeOdds

Sinkhole risk in Westchester 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
11%
At or near the surface
0%
Buried under cover
11%

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 47 of Westchester County's 431 square miles on soluble rock. With about 1,006,447 residents (2,336 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 547 map points about 0.9 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why the 11% under cover still counts, and how these percentages are measured.

Counties around Westchester County

The nearest county rated sinkhole country is Union County, PA, about 173 miles west. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

What Westchester County is built on

The largest mapped soluble unit here is the Inwood Marble (marble), Early Cambrian - Lower Ordovician in age, covering about 10% of the county. Next is the Manhattan Formation (A Member) at under 1%.

Against the rest of New York

Westchester County ranks 60 of 62 in New York for soluble rock at the surface, and sits above 0% of US counties on that measure.