Sinkhole risk in Huntington County, IN: 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: 100%
At or near the surface: under 1%
Buried under cover: 100%

What to do about a house in Huntington County

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

That works out to roughly 383 of Huntington County's 383 square miles on soluble rock, 1 of them with the rock at or near the surface. With about 36,944 residents (97 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 399 map points about 1.0 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why the 100% under cover still counts, and how these percentages are measured.

Counties around Huntington County

The nearest county rated sinkhole country is Barry County, MI, about 122 miles north. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Wells County, IN 15 mi southeast · under 1% at surface
Wabash County, IN 17 mi west · 0% at surface
Whitley County, IN 21 mi north · 0% at surface
Grant County, IN 23 mi southwest · 0% at surface
Blackford County, IN 26 mi south · 0% at surface
Allen County, IN 28 mi northeast · 0% at surface

Which formation it is

The largest mapped soluble unit here is the Wabash Formation (limestone), Silurian in age, covering about 88% of the county. Next is the Pleasant Mills Formation at 8%.

Against the rest of Indiana

Huntington County ranks 30 of 92 in Indiana for soluble rock at the surface, and sits above 51% of US counties on that measure.