Building Setbacks & Zoning in McHenry County, IL (2026)
3 rules for unincorporated McHenry County, Illinois.
Verified from official government sources
Setback Rules
In unincorporated McHenry County, residential and agricultural principal buildings generally need a 30-foot street setback, a 10-foot interior side setback, and a 20-30 foot rear setback (Table 16.36-1). Detached accessory structures must sit at least 10 feet from any lot line.
McHenry County Setbacks: 30 ft Street, 10 ft Side, Accessory 10 ft
Some RestrictionsMcHenry County Code § 16.56.050(A)(1)(d)
Accessory structures shall be located a minimum of ten (10) feet from any lot line, unless otherwise specified by this Ordinance.
Structure Height Limits
In unincorporated McHenry County, principal buildings in agricultural and residential districts are generally capped at 35 feet (38 feet in R-3). Detached accessory buildings are limited to 14 feet flat or 18 feet pitched in R districts, and 20-24 feet in estate/agricultural districts.
McHenry County Height Limits: 35 ft Homes, 14-18 ft Sheds
Some RestrictionsMcHenry County Code § 16.56.050(A)(2)(a)(2)
In the R-1, R-2, and R-3 Districts, detached accessory structures are limited to fourteen (14) feet in height for a flat or mansard roof design, and eighteen (18) feet in height for a pitched roof design.
Lot Coverage Limits
In unincorporated McHenry County, maximum building coverage is roughly 30-35% in residential/estate districts and maximum impervious surface is generally 50% (Table 16.36-1). In SARA and Class III resource-area overlays, impervious coverage is capped at 50% regardless of the underlying district.
McHenry County Lot Coverage: ~30-35% Building, 50% Impervious
Some RestrictionsMcHenry County Code § 16.52.040(E)(1)(a)
The maximum impervious surface coverage is limited to the lesser of the maximum impervious surface area allowed in the zoning district or fifty percent (50%), but in no case shall more than fifty percent (50%) of the SARA Overlay District area on site be made impervious.
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