Sinkhole risk in Kennebec County, ME: 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: 8%
At or near the surface: 0%
Buried under cover: 8%

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 69 of Kennebec County's 868 square miles on soluble rock. With about 128,461 residents (148 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 241 map points about 1.9 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why the 8% under cover still counts, and how these percentages are measured.

Counties around Kennebec County

The nearest county rated sinkhole country is Union County, PA, about 440 miles southwest. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Androscoggin County, ME 28 mi southwest · 0% at surface
Lincoln County, ME 32 mi southeast · 1% at surface
Waldo County, ME 32 mi east · 0% at surface
Sagadahoc County, ME 35 mi south · 0% at surface
Knox County, ME 44 mi southeast · under 1% at surface
Oxford County, ME 48 mi west · 0% at surface

Which formation it is

The largest mapped soluble unit here is the Silurian Sangerville Formation Patch Mountain member (marble), Silurian in age, covering about 4% of the county. Next is the Silurian Sangerville Formation limestone member at 4%.

Against the rest of Maine

Kennebec County ranks 9 of 16 in Maine for soluble rock at the surface, and sits above 0% of US counties on that measure.