Glacier County

Glacier County permitting is split across three regimes. (1) Blackfeet Indian Reservation: Construction on tribal trust land or allotted trust parcels requires a Blackfeet Tribe land-use permit (administered by the Blackfeet Tribal Business Council Land Department) plus BIA realty review under 25 CFR Part 162 (residential leasing) and 25 CFR Part 169 (access rights-of-way) where applicable. Tribal home-site leases and assignments are the typical mechanism for residential development on trust land - fee-simple ownership is generally not available on trust parcels. ADU construction on reservation fee-simple parcels (small inholdings) follows non-tribal county process but tribal jurisdiction may still attach for some purposes. (2) Cut Bank (incorporated): city building department issues permits per state-adopted IRC 2018 with Montana amendments. SB 528 preemption applies. (3) Unincorporated non-reservation Glacier County: no county building department, no county zoning. ADU construction proceeds with state-level oversight only (Montana DEQ for septic, DNRC for wells, county floodplain administrator for SFHA permits). Note: SB 528 has NO application here since this strip contains no incorporated cities. Glacier County is in IECC climate zone 6B-7; St. Mary and the Rocky Mountain Front face elevated snow loads (60-90 psf typical, higher at the Glacier NP boundary).

Impact fees: Glacier County levies no impact fees. SB 528 prohibits ADU-specific impact fees in Cut Bank. Reservation parcels are not subject to state or county impact fees but may carry tribal infrastructure assessments where applicable.

Property assessment in Montana is centralized at the Montana Department of Revenue (DOR), not the county. The Glacier County DOR field operations are administered through the Cut Bank office. Critically, tribal trust land is NOT subject to state or county property taxation (under the federal trust doctrine and 25 U.S.C. § 5108 immunity); the DOR assesses only fee-simple parcels (Cut Bank, unincorporated non-reservation, and the limited fee-simple parcels within the reservation boundary). Allotted trust parcels held by individual tribal members are likewise tax-exempt while in trust. ADU additions on fee-simple parcels are captured on the next biennial reappraisal cycle. Mont. Code Ann. § 15-6-134 establishes Class 4 residential property; MCA § 15-6-222 establishes the homestead exemption. Reservation residential improvements are recorded by Blackfeet Tribe and BIA but do not flow to the state tax roll.

Assessment policy: Improvement value for an ADU is added to fee-simple parcel records on the next biennial revaluation. Trust land parcels are tax-exempt and not assessed by DOR. Class 4 residential rate (~1.35% of market value, adjusting per legislative session) applies. Homestead / principal-residence treatment under MCA § 15-6-222 (and HB 231 2025 adjustments) shields the existing structure but new improvement value is fully captured on fee-simple parcels. Appeals run first to the Glacier County Tax Appeal Board (CTAB) and then to the Montana Tax Appeal Board.

Glacier County's overlay landscape is dominated by federal and tribal land management. Six categories are material: (1) Blackfeet Indian Reservation tribal jurisdiction - covers approximately 65% of county area; tribal land-use authority preempts state and county zoning; trust land is also tax-exempt. (2) Glacier National Park boundary - the park's east entrance (St. Mary, Many Glacier, Two Medicine, Cut Bank Creek) abuts the western edge of the county; NPS has no direct authority over private land but federal-action triggers can apply. (3) Wildland-Urban Interface - Glacier NP, the Bob Marshall Wilderness Complex (Sawtooth Range, Rocky Mountain Front), and tribal forest land all generate WUI exposure; the 2017 Sprague Fire and other recent burns have driven elevated insurance underwriting caution. (4) FEMA NFIP floodplain along the St. Mary River, Two Medicine River, Cut Bank Creek, Milk River. (5) Grizzly bear recovery zone - the Northern Continental Divide Ecosystem (NCDE) covers most of western Glacier County; ESA Section 7 consultation can apply to federally-financed construction. (6) NRHP historic resources - the Going-to-the-Sun Road National Historic Landmark (within Glacier NP), Cut Bank historic structures, and Blackfeet cultural resource sites administered through Blackfeet THPO and Montana SHPO.

• Blackfeet Indian Reservation - tribal land-use jurisdiction — The tribal/non-tribal jurisdictional split is the most important single factor for ADU work in Glacier County. Builders must determine parcel jurisdiction before any other planning. Trust-land home-site leasing through Blackfeet Tribe is a different model than fee-simple ownership and produces a very different ADU economics profile (no resale fee-simple, generation-to-generation lease assignments).
• Wildland-Urban Interface - Glacier NP, Bob Marshall Wilderness Complex, Rocky Mountain Front — ADU economics in St. Mary, Many Glacier, and East Glacier Park face elevated insurance cost (15-30% premium) and tightening underwriter availability. Tourism-driven STR demand offsets some of the cost where it is permitted. Cut Bank (eastern county, on the Plains) is essentially outside the WUI overlay.
• FEMA NFIP Special Flood Hazard Areas - St. Mary River, Two Medicine River, Cut Bank Creek, Milk River — Spring snowmelt drives late-spring flooding peaks; Glacier NP is the source of the St. Mary and Two Medicine drainages. ADUs in mapped SFHA must be elevated to or above Base Flood Elevation; this can add $20,000-$40,000 to construction cost.
• Glacier National Park boundary / east entrance corridor — STR demand in St. Mary, Many Glacier, and East Glacier Park is among the most concentrated in Montana, driven by Glacier NP tourism. Reservation jurisdiction in St. Mary and East Glacier Park complicates fee-simple ADU economics; many lodging operations are tribal lease-held.
• Northern Continental Divide Ecosystem (NCDE) Grizzly Bear Recovery Zone — Cash and conventional-financed ADUs face minimal direct ESA friction but bear-resistant storage compliance is widespread practice. Federally-financed projects can face 60-180 day Section 7 consultation timelines.
• Going-to-the-Sun Road NHL; Cut Bank historic structures; Blackfeet cultural resources — ADU work on Blackfeet reservation land triggers Blackfeet THPO consultation. ADU work on NRHP-listed contributing properties triggers Section 106 review only if federal financing or permitting (FHA, USDA RD, HUD-184) is involved.