Sinkhole risk in Suffolk County, NY: No soluble rock mapped

What to do about a house in Suffolk County

No soluble bedrock is mapped here, so natural sinkholes are unlikely. Collapses from broken pipes or old mines are a separate risk.

Across 911 square miles, under one square mile of Suffolk County maps onto soluble rock. With about 1,535,909 residents (1,686 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 320 map points about 1.7 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: how these percentages are measured, and the warning signs that apply anywhere.

Counties around Suffolk County

The nearest county rated sinkhole country is Union County, PA, about 228 miles west. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

• South Central Connecticut Planning Region, CT 25 mi north · 0% at surface
• Greater Bridgeport Planning Region, CT 32 mi northwest · 0% at surface
• Lower Connecticut River Valley Planning Region, CT 35 mi north · 0% at surface
• Naugatuck Valley Planning Region, CT 45 mi northwest · 0% at surface
• Western Connecticut Planning Region, CT 46 mi northwest · 0% at surface
• Southeastern Connecticut Planning Region, CT 48 mi northeast · 0% at surface

Against the rest of New York

Suffolk County ranks 52 of 62 in New York for soluble rock at the surface, and sits above 0% of US counties on that measure.

• New York County under 1%
• St. Lawrence County under 1%
• Saratoga County under 1%
• Cayuga County under 1%
• Clinton County under 1%