Sinkhole risk in Grant 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: 4%
At or near the surface: 4%
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 172 of Grant County's 4,528 square miles on soluble rock, 172 of them with the rock at or near the surface. With about 7,093 residents (2 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 365 map points about 3.5 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: how these percentages are measured, and the warning signs that apply anywhere.

Counties around Grant County

The nearest county rated sinkhole country is Emery County, UT, about 571 miles southeast. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Wheeler County, OR 53 mi west · 0% at surface
Baker County, OR 67 mi east · 14% at surface
Morrow County, OR 70 mi northwest · 0% at surface
Crook County, OR 71 mi west · 0% at surface
Union County, OR 75 mi northeast · under 1% at surface
Umatilla County, OR 77 mi north · under 1% at surface

The rock underneath

The largest mapped soluble unit here is the Sedimentary rocks, partly metamorphosed (Triassic and Paleozoic) (argillite), Paleozoic to Triassic in age, covering about 3% of the county. Next is the Sedimentary rocks, partly metamorphosed (Paleozoic) at under 1%.

Against the rest of Oregon

Grant County ranks 3 of 36 in Oregon for soluble rock at the surface, and sits above 61% of US counties on that measure.