Yellowstone County, MT Solar Energy: Panel Permits (2026)

B of the Yellowstone County Zoning Code splits solar installations into three tiers based on size and whether the power serves the site or is exported. A Tier 1 accessory system, building-mounted or ground-mounted, is capped at 2,000 square feet or 25% of the lot in residential and mixed-use districts and 4,000 square feet or 25% of the lot in agricultural, commercial, industrial, and public districts, whichever is less, and its height is limited to 10 feet in residential districts and 20 feet elsewhere for ground-mounted units, or up to five feet above the roofline for building-mounted panels.

Tier 2 ground-mounted systems in the I1 district can run up to 10 acres and up to 20 acres in I2, and any Tier 2 SEF sited in a commercial or industrial district must keep a 100-foot setback between the installation boundary and any residential district; Tier 3 size is set case by case through special review. 8, all submitted through the permitting process described in Section 27-1600. Approved facilities must also file an annual compliance statement confirming the system is active and giving current owner and emergency contact information.

Every SEF, regardless of tier, must avoid siting over a septic system or leach field without Department of Environmental Quality approval, use only motion-activated, fully shielded lighting if lighting is installed, and be enclosed by a six-foot fence (eight feet if topped with razor or barbed wire) unless the project runs full-time security or video surveillance.