Sinkhole risk in Deer Lodge County, MT: 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: 10%
At or near the surface: 10%
Buried under cover: 0%

The next step for one property

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

That works out to roughly 71 of Deer Lodge County's 737 square miles on soluble rock, 71 of them with the rock at or near the surface. With about 9,811 residents (13 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 469 map points about 1.3 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Deer Lodge County

The nearest county rated sinkhole country is Emery County, UT, about 505 miles south. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Granite County, MT 25 mi northwest · 17% at surface
Silver Bow County, MT 27 mi southeast · 10% at surface
Ravalli County, MT 46 mi west · 5% at surface
Jefferson County, MT 52 mi east · 6% at surface
Powell County, MT 53 mi north · 13% at surface
Beaverhead County, MT 67 mi south · 10% at surface

What Deer Lodge County is built on

The largest mapped soluble unit here is the Cambrian, undifferentiated (carbonate), Cambrian in age, covering about 5% of the county. Next is the Devonian, undifferentiated at 2%.

Against the rest of Montana

Deer Lodge County ranks 19 of 56 in Montana for soluble rock at the surface, and sits above 68% of US counties on that measure.