Sinkhole risk in Ramsey County, MN: 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: 93%
At or near the surface: 0%
Buried under cover: 93%

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 141 of Ramsey County's 152 square miles on soluble rock. With about 542,015 residents (3,560 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 353 map points about 0.7 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why the 93% under cover still counts, and how these percentages are measured.

Counties around Ramsey County

The nearest county rated sinkhole country is Vernon County, WI, about 149 miles southeast. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Washington County, MN 10 mi east · 0% at surface
Hennepin County, MN 18 mi west · 0% at surface
Anoka County, MN 19 mi north · 0% at surface
Dakota County, MN 24 mi south · 0% at surface
St. Croix County, WI 32 mi east · 1% at surface
Scott County, MN 33 mi southwest · 0% at surface

The rock underneath

The largest mapped soluble unit here is the Middle Ordovician rocks, undivided (shale), Middle Ordovician in age, covering about 52% of the county. Next is the Lower Ordovician rocks, undivided at 28%.

Against the rest of Minnesota

Ramsey County ranks 64 of 87 in Minnesota for soluble rock at the surface, and sits above 0% of US counties on that measure.