St. Clair County, IL Building Setbacks & Zoning: Structure Height Limits (2026)

St. Clair County's Zoning Code sets maximum building height by zoning district in the Schedule of Minimum Area, Bulk, and Yard Requirements at Section 40-3-7. Every district that allows residential use, the "A" Agricultural District, RR-3, RR-1, SR-1, SR-2, SR-3, SR-MH, MHP, MR-1, and MR-2, caps the principal building at 35 feet. Note 4 to the table states it directly for the "A" District: the maximum height of the principal building, excluding buildings and structures used for governmental purposes, is 35 feet, while buildings and structures used for governmental purposes may reach no more than 100 feet.

The same 35-foot figure appears as a direct entry in column L for the other nine residential districts; only the two industrial districts (I-1, I-2) and the B-2 business district are allowed to build higher, to 45 feet. Column M of the same schedule caps every accessory building or accessory use, detached garages, pole barns, tool sheds, at 25 feet regardless of district, with a minimum 10-foot separation from the principal building. Section 40-2-2 defines "BUILDING HEIGHT" as the vertical distance from the average elevation of the finished grade at the front wall to the highest point of the coping of a flat roof, the deck line of a mansard roof, or the mean height between eaves and ridge on a gable, hip, or gambrel roof; a roofless structure is measured from its lowest finished grade to its highest point.

Section 40-3-6 establishes the schedule as an integral, binding part of the Zoning Code, amendable only the same way as any other provision, originally adopted by Ordinance 95-12 on May 30, 1995.