Sinkhole risk in Delta County, MI: Pockets of it

Pockets of it

Soluble rock at the surface or under thin cover in part of the county.

On soluble rock: 73%
At or near the surface: 0%
Buried under cover: 73%

What to do about a house in Delta County

Check the parcel against your state survey sinkhole map, and ask for an inspection if cracks, depressions or sticking doors show up.

That works out to roughly 860 of Delta County's 1,171 square miles on soluble rock. With about 36,687 residents (31 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 271 map points about 2.1 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Delta County

The nearest county rated sinkhole country is Emmet County, MI, about 94 miles east. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Menominee County, MI 34 mi southwest · under 1% at surface
Schoolcraft County, MI 37 mi northeast · 1% at surface
Dickinson County, MI 49 mi west · 0% at surface
Door County, WI 50 mi south · under 1% at surface
Alger County, MI 51 mi north · 0% at surface
Leelanau County, MI 61 mi southeast · 7% at surface

The rock underneath

The largest mapped soluble unit here is the Trenton Limestone (limestone), Upper Ordovician in age, covering about 43% of the county. Next is the Stonington Formation at 9%.

Against the rest of Michigan

Delta County ranks 29 of 83 in Michigan for soluble rock at the surface, and sits above 0% of US counties on that measure.