Sinkhole risk in Breckinridge County, KY: Sinkhole country

Sinkhole country

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

On soluble rock: 90%
At or near the surface: 89%
Buried under cover: under 1%

What to do about a house in Breckinridge County

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

That works out to roughly 510 of Breckinridge County's 570 square miles on soluble rock, 505 of them with the rock at or near the surface. With about 21,221 residents (37 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 248 map points about 1.5 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why gypsum and salt move faster than limestone, and the signs to look for and how an inspection works.

Counties around Breckinridge County

The closest county with no soluble rock mapped is Spencer County, IN, about 35 miles northwest. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Meade County, KY 18 mi northeast · 91% at surface
Hancock County, KY 20 mi west · 6% at surface
Grayson County, KY 23 mi south · 60% at surface
Perry County, IN 23 mi northwest · 49% at surface
Hardin County, KY 26 mi east · 89% at surface
Ohio County, KY 31 mi southwest · 4% at surface

What Breckinridge County is built on

The largest mapped soluble unit here is the Rocks of Chesterian age, lower part (limestone), Upper Mississippian in age, covering about 57% of the county. Next is the Rocks of Chesterian age, upper part at 17%.

The county also lies over the Illinois Basin, a deep salt or gypsum basin. Deep beds rarely cause surface collapse on their own, but wells and mining into them have.

Against the rest of Kentucky

Breckinridge County ranks 12 of 120 in Kentucky for soluble rock at the surface, and sits above 96% of US counties on that measure.