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

Section 350-43A(5), Accessory use development and operational standards, applies to all accessory uses and structures countywide unless a specific district rule says otherwise. It bars any accessory structure, which includes sheds, from a required exterior setback outright. In the interior rear setback, accessory structures other than fences must still be set back at least three feet from the rear lot line and cannot come closer to the side lot line than the applicable minimum interior setback; fences may be built in that area. Interior side setbacks generally exclude accessory structures too, though a detached building in a rear yard may sit closer than the district's side setback provided it stays at least three feet from any lot line.

Height is capped by cross-reference: no accessory structure may exceed the maximum height standard of the underlying zoning district unless specifically authorized, which in the R-1 and R-2 residential districts works out to a 12-foot side wall limit under Sections 350-36E(2) and 350-37E(2). Building coverage is capped the same way, at the underlying district's maximum, and unless a shed is attached to the principal structure it must sit at least five feet from any other building on the lot. Section 350-16 separately requires a construction permit from the Director of Building and Zoning for most new structures, though light standards, birdhouses, flagpoles and similar minor accessory items under 36 inches are exempted from that permit.