McLean County, IL Outdoor Lighting: Dark Sky Rules (2026)

The county's only outdoor-lighting shielding standard tied to a specific land use sits inside the data center conditions of Article VI, § 350-43FFF(2): lighting must be installed for security and safety purposes only and shielded so no glare extends substantially beyond the boundaries of the facility. That means a data center operator cannot install decorative, sign, or general-purpose lighting, only fixtures needed for security and safety, and every one of those fixtures must carry shielding that keeps glare from crossing onto neighboring parcels. The requirement sits alongside the facility's other siting conditions, including the 500-foot landscaping screen of § 350-43FFF(1), so a facility close to homes has to control both sightlines and light spill.

Compliance is reviewed by the Director of Building and Zoning as part of site plan and special use approval, and the County Board can attach additional conditions when it grants the underlying special use permit. Because Chapter 350 is the county's zoning code, this shielding duty binds unincorporated county land; Bloomington and Normal set their own lighting rules for facilities inside their corporate limits. McLean County has not adopted a general dark-sky ordinance covering all outdoor lighting county-wide; this shielding standard is specific to data centers and does not extend to residential yard lights, farm lighting, or other commercial uses absent a comparable use-specific standard.