Sinkhole risk in Ford County, IL: 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: 49%
At or near the surface: 0%
Buried under cover: 49%

What this means before you buy

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

That works out to roughly 240 of Ford County's 486 square miles on soluble rock. With about 13,451 residents (28 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 429 map points about 1.1 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why gypsum and salt move faster than limestone, and why the 49% under cover still counts.

Counties around Ford County

The nearest county rated sinkhole country is Monroe County, IN, about 134 miles southeast. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Iroquois County, IL 23 mi northeast · 0% at surface
Livingston County, IL 27 mi northwest · 0% at surface
Champaign County, IL 32 mi south · 0% at surface
McLean County, IL 33 mi west · 0% at surface
Vermilion County, IL 39 mi southeast · 0% at surface
Kankakee County, IL 42 mi northeast · 6% at surface

The rock underneath

The largest mapped soluble unit here is the Silurian (dolostone (dolomite)), Silurian in age, covering about 35% of the county. Next is the Middle Devonian at 11%.

The county also lies over the Illinois Basin, 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 Illinois

Ford County ranks 49 of 102 in Illinois for soluble rock at the surface, and sits above 0% of US counties on that measure.