Building Setbacks & Zoning in St. Clair County, IL (2026)
3 rules for unincorporated St. Clair County, Illinois.
Verified from official government sources
Setback Rules
Unincorporated St. Clair County sets minimum yard setbacks by zoning district in Zoning Code Section 40-3-7. Every agricultural and residential district, from "A" Agricultural through "SR-3" Single Family Residence, carries a 25-foot front yard and a 25-foot side yard facing a street; only rear and side yard minimums shrink as lot size drops, from 40 feet of combined side yard in the "A" district to 15 feet in "SR-3." The Zoning Administrator enforces the table.
Yard Setbacks by Zoning District
Some RestrictionsSt. Clair County Zoning Code § 40-3-7
40-3-7 MINIMUM AREA, BULK, YARD REQUIREMENTS ... 4 SR-1 1 per 20,000 sq. ft. 20,000 sq. ft. 100' 150' 25' 25' 30 15 ... 5 SR-2 1 per 15,000 sq. ft. 15,000 sq. ft. 100' 125' 25' 25' 25 10 ... 6 SR-3 1 per 10,000 sq. ft. 10,000 sq. ft. 75' 100' 25' 25' 15 5 ... 4 30' 25' 20% 35' 25' 10' 60' 25' 5' 5' ... 5 20' 25' 20% 35' 25' 10' 60' 25' 5' 5' ... 6 15' 25' 20% 35' 25' 10' 60' 25' 5' 5' ... Note ...
Structure Height Limits
St. Clair County caps residential building height at 35 feet across every zoning district that allows a dwelling, from the Agricultural "A" District through RR-3, RR-1, SR-1, SR-2, SR-3, SR-MH, MHP, MR-1 and MR-2, under the Area/Bulk Yard Schedule at Zoning Code Section 40-3-7. Accessory buildings are capped separately at 25 feet, and government buildings in the "A" District may reach 100 feet under Note 4.
Residential Structure Height Limits in St. Clair County
Some RestrictionsSt. Clair County Zoning Ordinance Sec. 40-3-6(B)(1), Sec. 40-3-7, Note 4
...maximum principal building height shall be indicated in column "L"; maximum heights for accessory buildings and uses shall be indicated in column "M"... Note 4: The maximum of height of the principal building, excluding buildings and structures used for governmental purposes, shall be 35 ft. Buildings and structures used for governmental purposes shall have a maximum of no more than 100 ft.
Lot Coverage Limits
Unincorporated St. Clair County caps how much of a lot a building can cover under Zoning Code Sec. 40-3-7's bulk table. Agricultural (A) and three-acre Rural Residential (RR-3) lots carry no numeric coverage cap, RR-1 through SR-3 residential lots max out at 20%, SR-MH through B-1 districts top out at 30%, and B-2, I-1 and I-2 lots can cover up to 40%.
Max Lot Coverage Limits in St. Clair County, IL
Some RestrictionsSt. Clair County Zoning Ordinance Sec. 40-3-7 (Column K, Maximum Coverage)
40-3-7 MINIMUM AREA, BULK, YARD REQUIREMENTS ... K MAXIMUM COVERAGE IN % OF LOT ... 1 A --- 2 RR-3 --- 3 RR-1 20% 4 SR-1 20% 5 SR-2 20% 6 SR-3 20% 7 SR-MH 30% 8 MHP 30% 9 MR-1 30% 10 MR-2 30% 11 NB 30% 12 HB 30% 13 B-1 30% 14 B-2 40% 15 I-1 40% 16 I-2 40%
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