Sinkhole risk in Carroll County, MD: 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: 2%
At or near the surface: 2%
Buried under cover: 0%

What to do about a house in Carroll County

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

That works out to roughly 11 of Carroll County's 448 square miles on soluble rock, 11 of them with the rock at or near the surface. With about 177,108 residents (396 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 254 map points about 1.3 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Carroll County

The nearest county rated sinkhole country is Washington County, MD, about 43 miles west. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Frederick County, MD 21 mi west · 13% at surface
Howard County, MD 22 mi south · under 1% at surface
Baltimore County, MD 23 mi east · 8% at surface
Adams County, PA 24 mi northwest · 6% at surface
Baltimore city, MD 28 mi southeast · 0% at surface
York County, PA 29 mi northeast · 10% at surface

Which formation it is

The largest mapped soluble unit here is the Wakefield Marble (marble), Late Precambrian (?) in age, covering about 2% of the county. Next is the Silver Run Limestone at under 1%.

Against the rest of Maryland

Carroll County ranks 14 of 24 in Maryland for soluble rock at the surface, and sits above 59% of US counties on that measure.