Sinkhole risk in Sullivan County, IN: No soluble rock mapped

What to do about a house in Sullivan County

No soluble bedrock is mapped here, so natural sinkholes are unlikely. Collapses from broken pipes or old mines are a separate risk.

Across 447 square miles, under one square mile of Sullivan County maps onto soluble rock. With about 20,768 residents (46 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 342 map points about 1.1 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why gypsum and salt move faster than limestone, and how these percentages are measured.

Counties around Sullivan County

The nearest county rated sinkhole country is Monroe County, IN, about 48 miles east. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

• Crawford County, IL 19 mi west · 0% at surface
• Greene County, IN 22 mi east · 20% at surface
• Vigo County, IN 24 mi north · 0% at surface
• Clark County, IL 26 mi northwest · 0% at surface
• Clay County, IN 26 mi northeast · 0% at surface
• Knox County, IN 28 mi south · 0% at surface

Against the rest of Indiana

Sullivan County ranks 81 of 92 in Indiana for soluble rock at the surface, and sits above 0% of US counties on that measure.

• Harrison County 94%
• Orange County 90%
• Crawford County 83%
• Lawrence County 71%
• Washington County 62%