Outdoor Lighting in Cook County, IL (2026)

3 county-level rules, plus city-specific rules for 8 cities in Cook County, Illinois.

Verified from official government sources

Note: These county rules apply to unincorporated areas of Cook County. If you live within an incorporated city, that city's own rules apply: see the city list below.

Dark Sky Rules

Cook County's Lighting Ordinance directs County Departments to shield outdoor fixtures on County-owned roads, buildings and properties, capping light spilling onto neighboring lots at 0.1 footcandle. It binds County facilities only: private homes and businesses in Cook County are not covered.

Cook County Lighting Ordinance Covers County Facilities Only

Light Restrictions

Cook County Code § 2-341

Purpose. The purpose of the Cook County Lighting Ordinance is to achieve effective and efficient lighting, while:...(4)Allowing visual access to starry night skies....(d)Applicability. The requirements of this Code shall apply to all new and replacement lighting on roadways, developments, properties, buildings or structures under the jurisdiction of Cook County Departments.

Full ordinance details →Official source ↗

Light Trespass & Shielding

Cook County's Lighting Ordinance targets motion-activated security fixtures directly: sensor-activated lights on County property "should not be triggered by activity off the subject property" (Sec. 2-342(5)), and installations should pair sensors with timers or photocells to cut power in daylight. The rule binds County-operated lighting only, not a homeowner's floodlight.

Cook County Curbs Off-Property Security Light Triggers

Light Restrictions

Cook County Code § 2-342(5)

(5)Where practical, outdoor lighting installations are to include timers, dimmers, sensors, or photocell controllers that turn the lights off during daylight hours to reduce overall energy consumption and eliminate unnecessary lighting. Sensor activated fixtures should not be triggered by activity off the subject property.

Full ordinance details →Official source ↗

Billboard Lighting

In unincorporated Cook County's industrial-zoned areas, billboard and off-premises advertising signs cannot use strobe lights; indirect illumination must come from a steady, shielded light source aimed only at the sign face, per Cook County Code § 114-33.

Cook County Billboard Lighting Rules

Some Restrictions

Cook County Code § 114-33

(d)Signs shall not use strobe lights.(e)Signs which are indirectly illuminated shall be illuminated by a steady, stationary, shielded or shaded light source and shall be directed solely at the sign so that the light intensity or brightness does not shine on adjacent properties or create traffic hazards for motorists or pedestrians.(l)Signs shall not contain any fluttering, undulating, swinging,...

Full ordinance details →Official source ↗