Bolthole Index county-legal census · checked 2026-10-09
12 of Montana's 56 counties — 21% — set no minimum dwelling size. That is the 9th-largest count of any state. The strongest of them on the Bolthole Index is Sanders County (74/100). Every entry below cites the county’s own official source.
Rules change, and cities inside these counties set their own — treat this as a verified starting point, not legal advice. All 587 counties nationwide → Montana: no building codes → Montana: no zoning → Montana: no codes, no zoning → Montana: owner-builder → Montana: rv living → Montana: tiny homes → Full Montana profile →
12 of 56 Montana counties · sorted by Index score
County zoning minimum-dwelling-size standards in unincorporated Sanders County. The absence is limited to adopted zoning regulations; non-zoning building, health, wastewater, su…
Byrns Minor Subdivision Staff Report ↗Zoning-based minimum dwelling-size requirements in unincorporated Pondera County. This absence applies to county zoning regulations only. The City of Conrad and Town of Valier h…
2024 Pondera County Growth Policy ↗Minimum dwelling size in Judith Basin County unincorporated areas, to the extent regulated only through county zoning. The official state hazard-mitigation plan reports no count…
Central Montana Central Region Hazard Mitigation Plan, Annex I: Judith Basin County ↗Dwellings in unincorporated Teton County, where county zoning is absent Subdivision, septic, floodplain, building-code, and other applicable state or local requirements may stil…
Planner | Teton County Montana ↗Unincorporated Fergus County: no county rule sets this, because Fergus County's own reviewed answer confirms it has no county-wide zoning ordinance. Septic, floodplain, subdivis…
Central Montana Central Region Hazard Mitigation Plan, Annex F: Fergus County ↗County zoning minimum dwelling-size requirement in unincorporated Musselshell County. No county zoning ordinance is stated; state building-code and other non-zoning requirements…
About | Musselshell County ↗Unincorporated Treasure County: no county rule sets this, because Treasure County's own reviewed answer confirms it has no county-wide zoning ordinance. Septic, floodplain, subd…
Treasure County Growth Policy 2023 ↗County zoning-based minimum dwelling size requirements in unincorporated Rosebud County. The county growth policy states that municipal zoning exists in Colstrip and Forsyth; th…
Rosebud County Growth Policy ↗County zoning-based minimum dwelling size in Carter County. This conclusion is limited to county zoning; building, sanitation, subdivision, health, airport, and state rules may …
Carter County Growth Policy Update ↗County zoning minimum-dwelling-size requirements in the portions of unincorporated Dawson County that are outside the county's identified zoned areas. The source states that mos…
Zoning Information ↗County zoning-based minimum dwelling size in unincorporated Prairie County. This is an absence of a county zoning regulation; separate state building, health, sanitation, or sub…
2021 Prairie County Subdivision Regulations – Final Adopted ↗Unincorporated Petroleum County: no county rule sets this, because Petroleum County's own reviewed answer confirms it has no county-wide zoning ordinance. Septic, floodplain, su…
Central Montana Central Region Hazard Mitigation Plan, Annex K: Petroleum County ↗Every county here has a full profile — water, land prices, hazard safety, seclusion, and the rest of its building rules. See the Montana state page for all 56 counties ranked, or go back to the national list.
Off-grid gear
Building on land in one of these Montana counties? The kit we'd start with:
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General guidance, not legal advice. Off-grid, building, and land-use rules are often set at the county level and change often. Verify with your county and state before acting. Data reviewed 2026-06-26.
