Yellowstone County, MT Outdoor Lighting: Dark Sky Rules (2026)
Key Facts
- Shielding required
- Full cutoff, no light below shield
- Max pole height
- 15 feet
- Trigger distance
- Within 50 ft of residential zoning
- Applies to
- I1 and I2 industrial districts only
- Enforcing office
- County zoning coordinator
- Penalty
- Misdemeanor, fine or up to 6 months jail
Summary
In unincorporated Yellowstone County, industrial development within 50 feet of a residential zoning district must shield every outdoor light fixture with a full cutoff shield so no light escapes below it, and keep light poles at 15 feet or less. The Yellowstone County Zoning Code enforces this under Section 27-602.F.2 to stop industrial glare from spilling into neighborhood districts.
F. INDUSTRIAL USES LOCATED ADJACENT TO NEIGHBORHOOD AND RESIDENTIAL USES. All industrial districts and uses located within 50 feet of any neighborhood residential zoning district, including a planned development that allows residential use, shall comply with these site development standards: ... 2. All outdoor lighting, with the exception of signage, shall have full cutoff shields so no part of the fixture or lens projects below the cutoff shield. Light pole standards must be 15 feet in height or less.
Full Breakdown
Section 27-602 of the Yellowstone County Zoning Code governs any industrial use in the I1 (Light Industrial) or I2 (Heavy Industrial) district that sits within 50 feet of a neighborhood or residential zoning district, including a planned development that allows residential use. 2 states that all outdoor lighting, with the exception of signage, must have full cutoff shields so that no part of the fixture or lens projects below the cutoff shield, and it caps light pole standards at 15 feet in height or less.
6), reinforcing the no-glare intent for lighting adjacent to homes. 10 routes nonconforming lighting into Section 27-1100, Proportionate Compliance, so upgrades or expansions can trigger a shielding retrofit. The Planning & Community Services Department's zoning coordinator administers and enforces Article 27-600 as the designated zoning official under Section 27-1701. Because the shielding rule sits inside the industrial-districts chapter, it does not reach lighting on residential, agricultural, or commercial lots elsewhere in the county; it only applies where an industrial use directly borders or sits close to a residential zone.
A property owner who wants a taller pole or an unshielded fixture in that buffer must seek relief through the code's variance process under Section 27-1626 rather than installing noncompliant fixtures outright.
Violations & Fines
Installing an unshielded fixture or an oversized pole within the 50-foot residential buffer violates Section 27-602.F.2 and Section 27-1702's definition of a zoning violation. Under Section 27-1704.G, the violation is a misdemeanor punishable by a fine up to the state statutory limit, up to six months in the county jail, or both, plus all costs and expenses. Each day the noncompliant fixture stays up counts as a separate offense.
Frequently Asked Questions
Does this dark-sky rule apply to my house in unincorporated Yellowstone County?
What counts as a full cutoff shield under the county code?
Can an industrial pole exceed 15 feet if more coverage is needed?
What happens to lighting installed before this rule existed?
Sources & Official References
Other rules in Yellowstone County
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