Sinkhole risk in Bradford 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: 20%
Buried under cover: 80%

The next step for one property

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 294 of Bradford County's 294 square miles on soluble rock, 58 of them with the rock at or near the surface. With about 28,075 residents (96 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 480 map points about 0.8 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Bradford County

The nearest county rated sinkhole country is Union County, FL, about 14 miles northwest, 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.

Union County, FL 14 mi northwest · 50% at surface
Clay County, FL 18 mi east · 51% at surface
Alachua County, FL 22 mi southwest · 78% at surface
Baker County, FL 27 mi north · 21% at surface
Columbia County, FL 33 mi northwest · 40% at surface
Putnam County, FL 36 mi southeast · 7% at surface

Which formation it is

The largest mapped soluble unit here is the Hawthorn Group, Coosawhatchie Formation (limestone), Eocene in age, covering about 80% of the county. Next is the Hawthorn Group, Coosawhatchie Formation at 19%.

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

Bradford County ranks 49 of 67 in Florida for soluble rock at the surface, and sits above 74% of US counties on that measure.