Sinkhole risk in Marquette County, MI: 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: 22%
At or near the surface: 0%
Buried under cover: 22%

What to do about a house in Marquette County

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

That works out to roughly 396 of Marquette County's 1,809 square miles on soluble rock. With about 67,979 residents (38 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 251 map points about 2.7 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why the 22% under cover still counts, and how these percentages are measured.

Counties around Marquette County

The nearest county rated sinkhole country is Emmet County, MI, about 145 miles southeast. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Baraga County, MI 37 mi west · 0% at surface
Alger County, MI 45 mi east · 0% at surface
Dickinson County, MI 46 mi south · 0% at surface
Houghton County, MI 56 mi northwest · 0% at surface
Iron County, MI 57 mi southwest · 0% at surface
Keweenaw County, MI 61 mi northwest · 0% at surface

Which formation it is

The largest mapped soluble unit here is the Trempealeau Formation (sandstone), Upper Cambrian in age, covering about 8% of the county. Next is the Prairie du Chien Group at 6%.

Against the rest of Michigan

Marquette County ranks 57 of 83 in Michigan for soluble rock at the surface, and sits above 0% of US counties on that measure.