Sinkhole risk in Calhoun County, FL: Mostly deep or small

Mostly deep or small

Some soluble rock, mostly deeply buried or in a small share of the county.

On soluble rock: 61%
At or near the surface: 13%
Buried under cover: 47%

What this means before you buy

Sinkholes are uncommon here; watch for new depressions after heavy rain or leaking pipes.

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 343 of Calhoun County's 567 square miles on soluble rock, 75 of them with the rock at or near the surface. With about 13,278 residents (23 per square mile), much of the land is open, and the mapped rock may sit far from where people actually live. The figures come from 309 map points about 1.4 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 the 47% under cover still counts.

Counties around Calhoun County

The nearest county rated sinkhole country is Jackson County, FL, about 28 miles north, close enough that the same rock may run under the county line. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Liberty County, FL 22 mi southeast · 15% at surface
Bay County, FL 26 mi southwest · 0% at surface
Jackson County, FL 28 mi north · 87% at surface
Washington County, FL 31 mi northwest · 54% at surface
Gulf County, FL 37 mi south · 0% at surface
Gadsden County, FL 37 mi east · 33% at surface

What Calhoun County is built on

The largest mapped soluble unit here is the Alum Bluff Group (limestone), Eocene in age, covering about 34% of the county. Next is the Chattahoochee Formation at 6%.

Against the rest of Florida

Calhoun County ranks 52 of 67 in Florida for soluble rock at the surface, and sits above 70% of US counties on that measure.