Sinkhole risk in Montgomery County, IL: 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 to do about a house in Montgomery County

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

Across 704 square miles, under one square mile of Montgomery County maps onto soluble rock. With about 27,615 residents (39 per square mile), much of the land is open, and the mapped rock may sit far from where people actually live. The figures come from 263 map points about 1.6 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why gypsum and salt move faster than limestone, and how these percentages are measured.

Counties around Montgomery County

The nearest county rated sinkhole country is Calhoun County, IL, about 64 miles west. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Bond County, IL 24 mi south · 0% at surface
Macoupin County, IL 24 mi west · 0% at surface
Christian County, IL 24 mi northeast · 0% at surface
Fayette County, IL 29 mi southeast · 0% at surface
Madison County, IL 36 mi southwest · 0% at surface
Sangamon County, IL 38 mi north · 0% at surface

Against the rest of Illinois

Montgomery County ranks 79 of 102 in Illinois for soluble rock at the surface, and sits above 0% of US counties on that measure.