Sinkhole risk in Schoolcraft 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: 79%
At or near the surface: 1%
Buried under cover: 78%

What this means before you buy

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 926 of Schoolcraft County's 1,172 square miles on soluble rock, 13 of them with the rock at or near the surface. With about 8,178 residents (7 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 262 map points about 2.1 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why the 78% under cover still counts, and the signs to look for and how an inspection works.

Counties around Schoolcraft County

The nearest county rated sinkhole country is Emmet County, MI, about 65 miles southeast. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Delta County, MI 37 mi southwest · 0% at surface
Alger County, MI 41 mi northwest · 0% at surface
Charlevoix County, MI 42 mi southeast · 11% at surface
Mackinac County, MI 44 mi east · under 1% at surface
Luce County, MI 47 mi northeast · under 1% at surface
Leelanau County, MI 61 mi south · 7% at surface

What Schoolcraft County is built on

The largest mapped soluble unit here is the Trenton Limestone (limestone), Upper Ordovician in age, covering about 14% of the county. Next is the Black River Limestone at 14%.

Against the rest of Michigan

Schoolcraft County ranks 4 of 83 in Michigan for soluble rock at the surface, and sits above 56% of US counties on that measure.