SinkholeOdds

Sinkhole risk in Highlands County, FL: Pockets of it

Pockets of it

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

On soluble rock
100%
At or near the surface
7%
Buried under cover
93%

What this means before you buy

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

Standard Florida homeowners policies cover only catastrophic ground cover collapse; full sinkhole coverage is a separately priced option insurers must offer.

That works out to roughly 1,018 of Highlands County's 1,018 square miles on soluble rock, 69 of them with the rock at or near the surface. With about 109,778 residents (108 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 279 map points about 1.9 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: what Florida insurers have to cover, and why gypsum and salt move faster than limestone.

Counties around Highlands County

The nearest county rated sinkhole country is Glades County, FL, about 28 miles south, close enough that the same rock may run under the county line. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

What Highlands County is built on

The largest mapped soluble unit here is the Shelly sediments of Plio-Pleistocene age (beach sand), Holocene in age, covering about 48% of the county. Next is the Hawthorn Group, Coosawhatchie Formation at 36%.

The county also lies over the Floridan shelf, 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 Florida

Highlands County ranks 55 of 67 in Florida for soluble rock at the surface, and sits above 65% of US counties on that measure.