Sinkhole risk in Montgomery County, TN: Sinkhole country

Sinkhole country

Soluble rock at or near the surface across much of the county.

On soluble rock: 94%
At or near the surface: 94%
Buried under cover: 0%

What to do about a house in Montgomery County

Get a sinkhole or geotechnical inspection before buying, building or adding weight to a foundation.

That works out to roughly 506 of Montgomery County's 539 square miles on soluble rock, 506 of them with the rock at or near the surface. With about 246,025 residents (456 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 329 map points about 1.3 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Montgomery County

The closest county with no soluble rock mapped is Henry County, TN, about 53 miles west. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Cheatham County, TN 23 mi southeast · 39% at surface
Houston County, TN 23 mi southwest · 68% at surface
Stewart County, TN 24 mi west · 71% at surface
Dickson County, TN 25 mi south · 79% at surface
Todd County, KY 26 mi northeast · 91% at surface
Christian County, KY 28 mi north · 87% at surface

What Montgomery County is built on

The largest mapped soluble unit here is the St. Louis Limestone and Warsaw Limestone (limestone), Mississippian in age, covering about 75% of the county. Next is the St. Genevieve Limestone at 20%.

Against the rest of Tennessee

Montgomery County ranks 7 of 95 in Tennessee for soluble rock at the surface, and sits above 98% of US counties on that measure.