Sinkhole risk in Todd County, SD: Not karst, but voids possible

Not karst, but voids possible

No soluble bedrock; some pseudokarst (piping or lava-tube ground).

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

The next step for one property

Not true karst, but soil piping or lava tubes can still open voids - mention it to an inspector.

Across 1,389 square miles, under one square mile of Todd County maps onto soluble rock. With about 9,172 residents (7 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 384 map points about 1.9 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Todd County

The nearest county rated sinkhole country is Boyd County, NE, about 100 miles east. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Mellette County, SD 26 mi north · 0% at surface
Tripp County, SD 43 mi east · 3% at surface
Cherry County, NE 47 mi south · 0% at surface
Bennett County, SD 49 mi west · 0% at surface
Jones County, SD 51 mi north · 0% at surface
Keya Paha County, NE 55 mi southeast · 21% at surface

Against the rest of South Dakota

Todd County ranks 61 of 66 in South Dakota for soluble rock at the surface, and sits above 0% of US counties on that measure.