ADUs are allowed in Unincorporated YellowstoneTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Unincorporated Yellowstone, MT
Is your property eligible for an ADU?
# of Parcels
30,085
Zoning districts
11
Avg Parcel Value
$321,302
Median Parcel Size
1.53 acres
Zoning Districts:
1,239 parcels · 11 districts
RT
77%(953)
RMH
5%(64)
HI
4%(47)
HC
3%(43)
Other
11%(132)
ADU Rules
What can you build in Unincorporated Yellowstone, MT?
Unincorporated Yellowstone, MT follows state and local rules for Accessory Dwelling Units. Here is a concise overview of the local rules.
Eligibility
- –Internal / Attached ADU: By Right
- –Detached ADU: By Right
Interior / Attached ADU Size Limits
- –Maximum size equal to 100% of the primary dwelling’s gross floor area for attached or internal ADUs
Detached ADU Size Limits
- –Maximum detached ADU size is the lesser of 80% of the principal dwelling’s gross floor area and a lot-size cap: 750 sq ft for lots up to 20,000 sq ft or 1,000 sq ft for larger lots.
Max Units
- –1 per single-family lot
- –Duplex or multifamily lots: none specified
Owner Occupancy
- –Owner must occupy principal residence in either main dwelling or ADU
Parking
- –1 space/ADU required in N4; may be waived if space not feasible and/or on-street parking available without negatively impacting the neighborhood; on-street spaces adjacent to the property may count; parking for one- and two-unit dwellings must be on the same lot.
Rental Restrictions
- –STR limited to a guest home with Special Review; must be owner-occupied or have a long-term tenant for ≥180 days/year; if both a primary dwelling and ADU exist, only one unit may be an STR; no STR if the ADU is permanently affordable; owner must live in one dwelling ≥6 months/year and no third-party rentals in the owner-occupied unit.
What's allowed on your lot?
These are the municipality-wide rules. What's allowed on a specific property also depends on state laws, setbacks, floor area ratio, lot coverage, environmental constraints, topography, and other property-specific factors. Search your address on FutureLot to see what's allowed on your property.
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ADU rules in other Montana municipalities
Rules change at the town line. Check the municipality your property is actually in.
Yellowstone County