Sinkhole risk in Williamson 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: 46%
At or near the surface: 46%
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 508 of Williamson County's 1,116 square miles on soluble rock, 508 of them with the rock at or near the surface. With about 727,480 residents (652 per square mile), most of the county is built up, so a mapped unit is likely to sit under somebody's street. The figures come from 244 map points about 2.1 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Williamson County

The nearest county rated sinkhole country is Runnels County, TX, about 163 miles northwest. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Bell County, TX 28 mi north · 32% at surface
Travis County, TX 29 mi south · 57% at surface
Burnet County, TX 37 mi west · 63% at surface
Milam County, TX 38 mi east · 11% at surface
Bastrop County, TX 42 mi southeast · 4% at surface
Lee County, TX 44 mi southeast · 0% at surface

The rock underneath

The largest mapped soluble unit here is the Edwards and Comanche Peak Limestones, undivided (limestone), Early Cretaceous in age, covering about 17% of the county. Next is the Austin Chalk at 14%.

Against the rest of Texas

Williamson County ranks 56 of 254 in Texas for soluble rock at the surface, and sits above 86% of US counties on that measure.