SinkholeOdds

Sinkhole risk in Liberty 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
95%
At or near the surface
15%
Buried under cover
80%

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 790 of Liberty County's 836 square miles on soluble rock, 123 of them with the rock at or near the surface. With about 7,955 residents (10 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 538 map points about 1.2 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 Liberty County

The nearest county rated sinkhole country is Jackson County, FL, about 42 miles northwest. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

The rock underneath

The largest mapped soluble unit here is the Jackson Bluff Formation (limestone), Eocene in age, covering about 37% of the county. Next is the Intracoastal Formation at 33%.

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

Liberty County ranks 51 of 67 in Florida for soluble rock at the surface, and sits above 71% of US counties on that measure.