Sinkhole risk in St. Joseph County, IN: No soluble rock mapped

What to do about a house in St. Joseph County

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

Across 458 square miles, under one square mile of St. Joseph County maps onto soluble rock. With about 273,744 residents (598 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 354 map points about 1.1 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: how these percentages are measured, and the warning signs that apply anywhere.

Counties around St. Joseph County

The nearest county rated sinkhole country is Barry County, MI, about 83 miles northeast. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

• Marshall County, IN 20 mi south · 0% at surface
• Elkhart County, IN 22 mi east · 0% at surface
• LaPorte County, IN 24 mi west · 0% at surface
• Cass County, MI 25 mi northeast · 0% at surface
• Berrien County, MI 26 mi northwest · 0% at surface
• Starke County, IN 30 mi southwest · 0% at surface

Against the rest of Indiana

St. Joseph County ranks 77 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%