Is McCone County, MT a radon risk area?

EPA's own radon map rates McCone County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. McCone County sits at the 67th percentile nationally for radon potential — above 67 of every 100 rated counties.

How McCone County compares

About 1,717 people live in McCone County, Montana, spread over 2,642.225 square miles. Population density there runs about 1 people per square mile. Rank 1041 by population within its EPA zone puts McCone County at the 2nd percentile among zone peers. Geologically, McCone County is grouped into EPA Region 8 alongside 290 other counties that share its rock and soil setting.

What this actually means for a house in McCone County

McCone County's predicted average sits above EPA's own action level of 4 pCi/L — the concentration at which EPA recommends fixing a home — versus a national average around 1.3 pCi/L indoors and 0.4 pCi/L outdoors. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in McCone County will test well under the action level, and EPA's guidance is to test regardless of zone.

Testing and mitigation in McCone County

Nothing about McCone County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find Montana's state radon program

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

More on how this number was built

The methodology guide shows exactly which EPA and Census sources feed McCone County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.