Madison County, IL Accessory Structures: Shed & Carport Rules (2026)

051 of the zoning code sets accessory-building standards that apply across all agricultural, conservation, and residential districts in the unincorporated county. The maximum height is 20 feet in residential districts and 25 feet in agricultural and conservation districts, and no accessory building may exceed the height of the principal building on the lot. Every accessory structure must be at least 5 feet from any other building on the property. 5 feet from the rear lot line; in Conservation and Agricultural Districts the minimum jumps to 15 feet from both the side and rear lot lines.

Regardless of district, an accessory structure must stay at least 25 feet from any private roadway easement. Placement in the front yard is barred except on Agricultural-zoned tracts of two acres or more, where a shed or outbuilding may sit in front of the home. Corner-lot sheds may go in the side yard facing the street only if they meet the primary structure's front-yard setback and sit behind the front line of the house. Rear-yard coverage by accessory buildings cannot exceed 30%. 052 adds that no accessory building may be used for residential occupancy except as otherwise permitted, that modular homes are not allowed as accessory structures, and that an accessory structure permit on a vacant tract requires a concurrent building permit application for the primary structure.