Sinkhole risk in Montgomery County, MD: No soluble rock mapped

No soluble rock mapped

No soluble bedrock mapped.

On soluble rock: 0%
At or near the surface: 0%
Buried under cover: 0%

What this means before you buy

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

Across 493 square miles, under one square mile of Montgomery County maps onto soluble rock. With about 1,082,273 residents (2,195 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 523 map points about 1.0 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 Montgomery County

The nearest county rated sinkhole country is Jefferson County, WV, about 37 miles west, close enough that the same rock may run under the county line. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Howard County, MD 17 mi northeast · under 1% at surface
Falls Church city, VA 18 mi south · 0% at surface
Arlington County, VA 19 mi south · 0% at surface
District of Columbia, DC 19 mi southeast · 1% at surface
Fairfax city, VA 20 mi south · 0% at surface
Fairfax County, VA 22 mi south · 2% at surface

Against the rest of Maryland

Montgomery County ranks 20 of 24 in Maryland for soluble rock at the surface, and sits above 0% of US counties on that measure.