Sinkhole risk in Grayson County, TX: Pockets of it

Pockets of it

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

On soluble rock: 36%
At or near the surface: 36%
Buried under cover: 0%

What this means before you buy

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 334 of Grayson County's 933 square miles on soluble rock, 334 of them with the rock at or near the surface. With about 150,532 residents (161 per square mile), homes are spread across towns and farmland, and a mapped unit may or may not reach the developed parts. The figures come from 318 map points about 1.7 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: the signs to look for and how an inspection works, and how these percentages are measured.

Counties around Grayson County

The nearest county rated sinkhole country is Grady County, OK, about 119 miles northwest. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Marshall County, OK 28 mi north · 35% at surface
Collin County, TX 30 mi south · 47% at surface
Cooke County, TX 31 mi west · 52% at surface
Fannin County, TX 33 mi east · 25% at surface
Bryan County, OK 33 mi northeast · 18% at surface
Denton County, TX 39 mi southwest · 41% at surface

The rock underneath

The largest mapped soluble unit here is the Austin Chalk (limestone), Late Cretaceous; Gulfian Series in age, covering about 24% of the county. Next is the Gober Chalk and Roxton Limestone at 4%.

Against the rest of Texas

Grayson County ranks 74 of 254 in Texas for soluble rock at the surface, and sits above 82% of US counties on that measure.