Sinkhole risk in Gilchrist County, FL: Sinkhole country

Sinkhole country

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

On soluble rock: 100%
At or near the surface: 52%
Buried under cover: 48%

The next step for one property

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

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 350 of Gilchrist County's 350 square miles on soluble rock, 181 of them with the rock at or near the surface. With about 20,233 residents (58 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 318 map points about 1.0 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 Gilchrist County

The closest county with no soluble rock mapped is Gulf County, FL, about 149 miles west. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Alachua County, FL 27 mi east · 78% at surface
Dixie County, FL 29 mi southwest · 93% at surface
Lafayette County, FL 29 mi northwest · 41% at surface
Levy County, FL 31 mi south · 67% at surface
Suwannee County, FL 34 mi north · 40% at surface
Union County, FL 34 mi northeast · 50% at surface

The rock underneath

The largest mapped soluble unit here is the Ocala Limestone (limestone), Eocene in age, covering about 100% of the county.

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

Gilchrist County ranks 24 of 67 in Florida for soluble rock at the surface, and sits above 88% of US counties on that measure.