Out of 355 ZIP codes with data in Montana, these are the lowest-ranked areas for radon zone. See also: National ZIP Codes with Highest Radon Risk | All Montana Rankings
| Statistic | Value |
|---|---|
| ZIP codes ranked | 355 |
| Lowest value | Zone 1 (High) |
| Median value | Zone 1 (High) |
| State | Montana |
100 Lowest-Ranked ZIP Codes
| Rank | ZIP Code | City | State | Radon Zone | Safety Score |
|---|---|---|---|---|---|
| 1 | 59542 | Turner | MT | Zone 1 (High) | 22/100 |
| 2 | 59484 | Sweet Grass | MT | Zone 1 (High) | 28/100 |
| 3 | 59003 | Ashland | MT | Zone 1 (High) | 33/100 |
| 4 | 59004 | Ashland | MT | Zone 1 (High) | 33/100 |
| 5 | 59035 | Fort Smith | MT | Zone 1 (High) | 33/100 |
| 6 | 59858 | Philipsburg | MT | Zone 1 (High) | 33/100 |
| 7 | 59648 | Wolf Creek | MT | Zone 1 (High) | 34/100 |
| 8 | 59602 | Helena | MT | Zone 1 (High) | 37/100 |
| 9 | 59620 | Helena | MT | Zone 1 (High) | 37/100 |
| 10 | 59623 | Helena | MT | Zone 1 (High) | 37/100 |
| 11 | 59624 | Helena | MT | Zone 1 (High) | 37/100 |
| 12 | 59625 | Helena | MT | Zone 1 (High) | 37/100 |
| 13 | 59626 | Helena | MT | Zone 1 (High) | 37/100 |
| 14 | 59230 | Glasgow | MT | Zone 1 (High) | 39/100 |
| 15 | 59007 | Bearcreek | MT | Zone 1 (High) | 40/100 |
| 16 | 59016 | Busby | MT | Zone 1 (High) | 40/100 |
| 17 | 59022 | Crow Agency | MT | Zone 1 (High) | 40/100 |
| 18 | 59025 | Decker | MT | Zone 1 (High) | 40/100 |
| 19 | 59031 | Garryowen | MT | Zone 1 (High) | 40/100 |
| 20 | 59043 | Lame Deer | MT | Zone 1 (High) | 40/100 |
| 21 | 59062 | Otter | MT | Zone 1 (High) | 40/100 |
| 22 | 59066 | Pryor | MT | Zone 1 (High) | 40/100 |
| 23 | 59077 | Sand Springs | MT | Zone 1 (High) | 40/100 |
| 24 | 59084 | Teigen | MT | Zone 1 (High) | 40/100 |
| 25 | 59089 | Wyola | MT | Zone 1 (High) | 40/100 |
| 26 | 59213 | Brockton | MT | Zone 1 (High) | 40/100 |
| 27 | 59214 | Brockway | MT | Zone 1 (High) | 40/100 |
| 28 | 59217 | Crane | MT | Zone 1 (High) | 40/100 |
| 29 | 59219 | Dagmar | MT | Zone 1 (High) | 40/100 |
| 30 | 59225 | Frazer | MT | Zone 1 (High) | 40/100 |
| 31 | 59240 | Glentana | MT | Zone 1 (High) | 40/100 |
| 32 | 59242 | Homestead | MT | Zone 1 (High) | 40/100 |
| 33 | 59244 | Larslan | MT | Zone 1 (High) | 40/100 |
| 34 | 59253 | Peerless | MT | Zone 1 (High) | 40/100 |
| 35 | 59256 | Raymond | MT | Zone 1 (High) | 40/100 |
| 36 | 59257 | Redstone | MT | Zone 1 (High) | 40/100 |
| 37 | 59258 | Reserve | MT | Zone 1 (High) | 40/100 |
| 38 | 59260 | Richland | MT | Zone 1 (High) | 40/100 |
| 39 | 59262 | Savage | MT | Zone 1 (High) | 40/100 |
| 40 | 59273 | Vandalia | MT | Zone 1 (High) | 40/100 |
| 41 | 59274 | Vida | MT | Zone 1 (High) | 40/100 |
| 42 | 59276 | Whitetail | MT | Zone 1 (High) | 40/100 |
| 43 | 59311 | Alzada | MT | Zone 1 (High) | 40/100 |
| 44 | 59312 | Angela | MT | Zone 1 (High) | 40/100 |
| 45 | 59314 | Biddle | MT | Zone 1 (High) | 40/100 |
| 46 | 59315 | Bloomfield | MT | Zone 1 (High) | 40/100 |
| 47 | 59316 | Boyes | MT | Zone 1 (High) | 40/100 |
| 48 | 59318 | Brusett | MT | Zone 1 (High) | 40/100 |
| 49 | 59319 | Capitol | MT | Zone 1 (High) | 40/100 |
| 50 | 59322 | Cohagen | MT | Zone 1 (High) | 40/100 |
| 51 | 59326 | Fallon | MT | Zone 1 (High) | 40/100 |
| 52 | 59332 | Hammond | MT | Zone 1 (High) | 40/100 |
| 53 | 59333 | Hathaway | MT | Zone 1 (High) | 40/100 |
| 54 | 59336 | Ismay | MT | Zone 1 (High) | 40/100 |
| 55 | 59339 | Lindsay | MT | Zone 1 (High) | 40/100 |
| 56 | 59341 | Mildred | MT | Zone 1 (High) | 40/100 |
| 57 | 59343 | Olive | MT | Zone 1 (High) | 40/100 |
| 58 | 59345 | Powderville | MT | Zone 1 (High) | 40/100 |
| 59 | 59349 | Terry | MT | Zone 1 (High) | 40/100 |
| 60 | 59351 | Volborg | MT | Zone 1 (High) | 40/100 |
| 61 | 59354 | Willard | MT | Zone 1 (High) | 40/100 |
| 62 | 59402 | Malmstrom A F B | MT | Zone 1 (High) | 40/100 |
| 63 | 59418 | Buffalo | MT | Zone 1 (High) | 40/100 |
| 64 | 59424 | Coffee Creek | MT | Zone 1 (High) | 40/100 |
| 65 | 59432 | Dupuyer | MT | Zone 1 (High) | 40/100 |
| 66 | 59434 | East Glacier Park | MT | Zone 1 (High) | 40/100 |
| 67 | 59440 | Floweree | MT | Zone 1 (High) | 40/100 |
| 68 | 59441 | Forest Grove | MT | Zone 1 (High) | 40/100 |
| 69 | 59448 | Heart Butte | MT | Zone 1 (High) | 40/100 |
| 70 | 59451 | Hilger | MT | Zone 1 (High) | 40/100 |
| 71 | 59457 | Lewistown | MT | Zone 1 (High) | 40/100 |
| 72 | 59461 | Lothair | MT | Zone 1 (High) | 40/100 |
| 73 | 59462 | Moccasin | MT | Zone 1 (High) | 40/100 |
| 74 | 59466 | Oilmont | MT | Zone 1 (High) | 40/100 |
| 75 | 59469 | Raynesford | MT | Zone 1 (High) | 40/100 |
| 76 | 59521 | Box Elder | MT | Zone 1 (High) | 40/100 |
| 77 | 59526 | Harlem | MT | Zone 1 (High) | 40/100 |
| 78 | 59527 | Hays | MT | Zone 1 (High) | 40/100 |
| 79 | 59529 | Hogeland | MT | Zone 1 (High) | 40/100 |
| 80 | 59530 | Inverness | MT | Zone 1 (High) | 40/100 |
| 81 | 59531 | Joplin | MT | Zone 1 (High) | 40/100 |
| 82 | 59532 | Kremlin | MT | Zone 1 (High) | 40/100 |
| 83 | 59535 | Lloyd | MT | Zone 1 (High) | 40/100 |
| 84 | 59633 | Canyon Creek | MT | Zone 1 (High) | 40/100 |
| 85 | 59638 | Jefferson City | MT | Zone 1 (High) | 40/100 |
| 86 | 59640 | Marysville | MT | Zone 1 (High) | 40/100 |
| 87 | 59641 | Radersburg | MT | Zone 1 (High) | 40/100 |
| 88 | 59642 | Ringling | MT | Zone 1 (High) | 40/100 |
| 89 | 59647 | Winston | MT | Zone 1 (High) | 40/100 |
| 90 | 59713 | Avon | MT | Zone 1 (High) | 40/100 |
| 91 | 59720 | Cameron | MT | Zone 1 (High) | 40/100 |
| 92 | 59727 | Divide | MT | Zone 1 (High) | 40/100 |
| 93 | 59728 | Elliston | MT | Zone 1 (High) | 40/100 |
| 94 | 59731 | Garrison | MT | Zone 1 (High) | 40/100 |
| 95 | 59732 | Glen | MT | Zone 1 (High) | 40/100 |
| 96 | 59733 | Gold Creek | MT | Zone 1 (High) | 40/100 |
| 97 | 59735 | Harrison | MT | Zone 1 (High) | 40/100 |
| 98 | 59740 | Mc Allister | MT | Zone 1 (High) | 40/100 |
| 99 | 59743 | Melrose | MT | Zone 1 (High) | 40/100 |
| 100 | 59746 | Polaris | MT | Zone 1 (High) | 40/100 |
Methodology
Radon rankings are based on EPA county-level radon zone classifications. Zone 1 (highest risk) has predicted average indoor radon levels above 4 pCi/L — the EPA action level. Zone 2 is moderate (2-4 pCi/L) and Zone 3 is low (below 2 pCi/L). Within Zone 1, ZIP codes are sub-ranked by Home Safety Score to prioritize areas with compounding risk factors.
Data sources: EPA Safe Drinking Water Information System (SDWIS), FEMA National Flood Insurance Program, EPA radon zone maps, EIA electricity rates, and Consumer Confidence Reports. Last updated: 2026-06-04.
Frequently Asked Questions
What is EPA Radon Zone 1?
Zone 1 is the EPA highest-risk classification, meaning the county has predicted average indoor radon levels above 4 pCi/L — the level at which the EPA recommends mitigation. Radon causes about 21,000 lung cancer deaths per year in the U.S.
Should I test for radon?
The EPA recommends testing all homes regardless of radon zone. A DIY test kit costs $15-40. Professional testing costs $150-250. If levels exceed 4 pCi/L, mitigation systems ($800-2,500) can reduce radon by up to 99%.
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