What EPA's radon map says about Henry County

EPA's own radon map rates Henry County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. That puts Henry County in the 47th percentile nationally for radon potential — higher than 47% of the counties EPA has rated.

How Henry County compares

About 22,575 people live in Henry County, Missouri, spread over 696.936 square miles. That works out to roughly 32 people per square mile. Among counties sharing Henry County's EPA zone, it outranks 43% of them by population. Geologically, Henry County is grouped into EPA Region 7 alongside 411 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

Henry County's Zone 2 prediction clears the 1.3 pCi/L national indoor average without reaching EPA's own 4 pCi/L point for recommending a fix. A county-wide moderate average, like Henry County's, can still hide a specific house well above or below it — testing is what actually answers the question.

Next steps for a home in Henry County

Mitigation cost doesn't depend on Henry County's zone — it depends on the house's foundation. A typical system runs $800–$2,500 (about $1,200 typical), and testing first is what tells you whether that's needed at all.

Find Missouri's state radon program

Henry County's test kit answers today; a Airthings radon monitor keeps answering for Henry County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Code RADONZONE-10OFF takes 10% off at checkout.

More on how this number was built

Henry County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.