Sinkhole risk in Llano County, TX: 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: 11%
At or near the surface: 11%
Buried under cover: 0%

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 106 of Llano County's 934 square miles on soluble rock, 106 of them with the rock at or near the surface. With about 23,163 residents (25 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 355 map points about 1.6 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Llano County

The nearest county rated sinkhole country is Runnels County, TX, about 110 miles northwest. None of the 6 closest counties land in the same band, so Llano County stands out from its surroundings.

Burnet County, TX 29 mi east · 63% at surface
Gillespie County, TX 31 mi southwest · 89% at surface
San Saba County, TX 32 mi north · 59% at surface
Mason County, TX 33 mi west · 46% at surface
Blanco County, TX 35 mi southeast · 90% at surface
Lampasas County, TX 43 mi northeast · 57% at surface

What Llano County is built on

The largest mapped soluble unit here is the Tanyard Formation (limestone), Early Ordovician in age, covering about 3% of the county. Next is the Wilberns Formation showing Point Peak, Morgan Creek Limestone, and Welge Sandstone Members, undivided at 3%.

Against the rest of Texas

Llano County ranks 114 of 254 in Texas for soluble rock at the surface, and sits above 69% of US counties on that measure.