Sinkhole risk in Lewis County, ID: No soluble rock mapped

No soluble rock mapped

No soluble bedrock mapped.

On soluble rock: under 1%
At or near the surface: under 1%
Buried under cover: 0%

What to do about a house in Lewis County

No soluble bedrock is mapped here, so natural sinkholes are unlikely. Collapses from broken pipes or old mines are a separate risk.

That works out to roughly 4 of Lewis County's 479 square miles on soluble rock, 4 of them with the rock at or near the surface. With about 3,728 residents (8 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 439 map points about 1.0 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 Lewis County

The nearest county rated sinkhole country is Emery County, UT, about 577 miles southeast. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Nez Perce County, ID 17 mi northwest · 3% at surface
Asotin County, WA 39 mi west · 0% at surface
Latah County, ID 43 mi north · 0% at surface
Clearwater County, ID 47 mi northeast · 0% at surface
Idaho County, ID 53 mi southeast · under 1% at surface
Garfield County, WA 55 mi west · 0% at surface

Which formation it is

The largest mapped soluble unit here is the Limestone, slate; Upper Triassic greenschist-facies metamorphic rocks; western Idaho, Blue Mountains island-arc complex; (limestone), Late Triassic in age, covering about under 1% of the county.

Against the rest of Idaho

Lewis County ranks 22 of 44 in Idaho for soluble rock at the surface, and sits above 55% of US counties on that measure.