Sinkhole risk in Lincoln County, MT: Pockets of it

Pockets of it

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

On soluble rock: 29%
At or near the surface: 29%
Buried under cover: 0%

The next step for one property

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 1,033 of Lincoln County's 3,613 square miles on soluble rock, 1,033 of them with the rock at or near the surface. With about 22,184 residents (6 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 301 map points about 3.5 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: the signs to look for and how an inspection works, and how these percentages are measured.

Counties around Lincoln County

The nearest county rated sinkhole country is Fall River County, SD, about 681 miles southeast. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Boundary County, ID 51 mi west · 0% at surface
Bonner County, ID 56 mi west · 1% at surface
Sanders County, MT 57 mi south · 20% at surface
Flathead County, MT 67 mi east · 25% at surface
Pend Oreille County, WA 81 mi west · 2% at surface
Kootenai County, ID 83 mi southwest · 0% at surface

What Lincoln County is built on

The largest mapped soluble unit here is the Wallace formation (meta-argillite), Middle-Proterozoic in age, covering about 23% of the county. Next is the Piegan group at 5%.

Against the rest of Montana

Lincoln County ranks 4 of 56 in Montana for soluble rock at the surface, and sits above 79% of US counties on that measure.