Sinkhole risk in Pontotoc County, OK: Pockets of it

Pockets of it

Soluble rock at the surface or under thin cover in part of the county.

On soluble rock: 28%
At or near the surface: 28%
Buried under cover: 0%

The next step for one property

Check the parcel against your state survey sinkhole map, and ask for an inspection if cracks, depressions or sticking doors show up.

That works out to roughly 200 of Pontotoc County's 720 square miles on soluble rock, 200 of them with the rock at or near the surface. With about 38,310 residents (53 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 307 map points about 1.5 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: the signs to look for and how an inspection works, and how these percentages are measured.

Counties around Pontotoc County

The nearest county rated sinkhole country is Grady County, OK, about 71 miles west. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Coal County, OK 25 mi southeast · 4% at surface
Murray County, OK 27 mi southwest · 49% at surface
Johnston County, OK 28 mi south · 33% at surface
Seminole County, OK 31 mi north · 34% at surface
Hughes County, OK 34 mi northeast · 0% at surface
Garvin County, OK 35 mi west · 0% at surface

The rock underneath

The largest mapped soluble unit here is the Vanoss Group (shale), Late Pennsylvanian in age, covering about 9% of the county. Next is the West Spring Creek Formation at 7%.

Against the rest of Oklahoma

Pontotoc County ranks 32 of 77 in Oklahoma for soluble rock at the surface, and sits above 78% of US counties on that measure.