Sinkhole risk in Floyd County, IN: Pockets of it

Pockets of it

Soluble rock at the surface or under thin cover in part of the county.

On soluble rock: 29%
At or near the surface: 29%
Buried under cover: under 1%

What to do about a house in Floyd County

Check the parcel against your state survey sinkhole map, and ask for an inspection if cracks, depressions or sticking doors show up.

That works out to roughly 44 of Floyd County's 148 square miles on soluble rock, 43 of them with the rock at or near the surface. With about 81,931 residents (552 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 263 map points about 0.8 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Floyd County

The nearest county rated sinkhole country is Harrison County, IN, about 14 miles southwest, close enough that the same rock may run under the county line. None of the 6 closest counties land in the same band, so Floyd County stands out from its surroundings.

Harrison County, IN 14 mi southwest · 94% at surface
Clark County, IN 15 mi northeast · 3% at surface
Jefferson County, KY 16 mi southeast · 59% at surface
Washington County, IN 22 mi northwest · 62% at surface
Oldham County, KY 25 mi east · 88% at surface
Scott County, IN 26 mi north · 2% at surface

What Floyd County is built on

The largest mapped soluble unit here is the Sanders Group (limestone), Mississippian in age, covering about 22% of the county. Next is the Blue River Group at 7%.

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 Indiana

Floyd County ranks 8 of 92 in Indiana for soluble rock at the surface, and sits above 79% of US counties on that measure.