Sinkhole risk in Douglas County, OR: 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: 1%
At or near the surface: 1%
Buried under cover: 0%

What to do about a house in Douglas County

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

That works out to roughly 55 of Douglas County's 5,036 square miles on soluble rock, 55 of them with the rock at or near the surface. With about 112,255 residents (22 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 530 map points about 3.1 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: how these percentages are measured, and the warning signs that apply anywhere.

Counties around Douglas County

The nearest county rated sinkhole country is Emery County, UT, about 710 miles east. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Lane County, OR 46 mi north · 0% at surface
Coos County, OR 48 mi west · 0% at surface
Jackson County, OR 65 mi south · 2% at surface
Josephine County, OR 66 mi south · 9% at surface
Curry County, OR 78 mi southwest · under 1% at surface
Benton County, OR 85 mi north · 0% at surface

Which formation it is

The largest mapped soluble unit here is the Sedimentary rocks of Dothan Formation and related rocks (Lower Cretaceous and Upper Jurassic) (mudstone), Late Jurassic to Late Cretaceous in age, covering about 1% of the county.

Against the rest of Oregon

Douglas County ranks 8 of 36 in Oregon for soluble rock at the surface, and sits above 56% of US counties on that measure.