Accessory Structures in Illinois (2026)

Des Plaines has no accessory dwelling unit (ADU) or coach-house ordinance; under Zoning Code Section 12-8-1 a permitted…

In unincorporated Kankakee County's agriculture, residence and rural estate districts, County Code § 121-283(b) allows…

Springfield's zoning code expressly prohibits using any detached garage, accessory building, or structure as a dwelling…

DuPage County allows one accessory dwelling unit per single-family lot, but only as a conditional use capped at 1,000…

Unincorporated Kendall County does not allow a standalone rental accessory dwelling unit: Section 36-971(a)(6) permits…

Macon County's zoning code does not allow guest houses, servants' quarters, apartments, or similar living units as…

Unincorporated Madison County allows accessory dwelling units only as a special use in the Agricultural District, on…

Peoria County allows one accessory dwelling per residential lot, but only within, or attached to, the principal…

Champaign allows one Accessory Dwelling Unit per lot, attached, detached, or internal, in any residential zoning…

Chicago's Zoning Ordinance caps coach houses, the classic garage-apartment ADU, at 22 feet in building height…

Accessory dwelling units in unincorporated Cook County are subject to the Cook County Zoning Ordinance (Ord. 01-O-30)…

Evanston allows one accessory dwelling unit per zoning lot, attached, internal, or detached, capped at 1,000 square…

Unincorporated Kane County allows only one residential building per zoning lot, so a standalone accessory dwelling unit…

In unincorporated Lake County, accessory dwelling units are capped at one bedroom and 1,000 square feet, and only…

Unincorporated McHenry County allows one ancillary dwelling unit per lot under UDO § 16.56.030O, attached to the house…

McLean County's zoning ordinance allows one guest household unit, a secondary living space with its own kitchen, as an…

St. Clair County's Zoning Ordinance does not authorize a standalone accessory dwelling unit. Residential districts…

Tazewell County allows one accessory dwelling per lot in residential and agricultural districts, but only if the same…

Waukegan allows one detached accessory dwelling unit per lot in the R1 through R5, L1, L2, and L3 districts, capped at…

Unincorporated Will County allows one accessory dwelling unit per lot with detached houses, capped at 650 square feet…

Chicago charges a $500 Affordable ADU Initial Registration Fee for each coach house or conversion unit an owner must…

In Chicago's designated Additional Dwelling Unit-Allowed RS Areas, a single-family lot can only add a coach house or…

Waukegan requires the owner of an accessory dwelling unit lot to live on the same property as the ADU, a residency…

Evanston does not require the property owner to live on-site to have an accessory dwelling unit, but the ADU must stay…

In unincorporated Lake County, the property owner must live in either the main house or the accessory dwelling unit for…

An accessory dwelling in unincorporated Tazewell County must be owned by the same person who occupies the habitable…

Will County requires the property owner to live in either the main house or the accessory dwelling unit at least six…

McLean County's guest household unit, the county's accessory dwelling option, cannot be rented out. Section…

Chicago bans short-term rental of new coach house ADUs; only long-term household occupants may use them.

In unincorporated Lake County, an accessory dwelling unit cannot be rented out as a separate income property while the…

Tazewell County's accessory dwelling standards flatly bar renting the unit to anyone outside the family: Section…

A backyard shed in Arlington Heights is capped at 300 square feet and must sit in the rear yard, at least three feet…

Aurora caps private sheds at 160 square feet and 14 feet in height, restricts them to rear yards only, and requires at…

A single-family lot in Bolingbrook may have one storage shed up to 12 feet tall and 200 square feet, and multi-family…

Champaign caps detached accessory structures, sheds, detached garages, and similar buildings, on single-family lots at…

Champaign County requires detached sheds and other accessory buildings on unincorporated land to sit at least 5 to 10…

Chicago zoning treats a carport as an unenclosed parking space: it can't sit in the required front setback, and…

Cicero bars murals or other artwork on a garage, shed or other storage building and limits paint to no more than three…

Carports in unincorporated Cook County require a building permit from the Department of Building and Zoning. They are…

Des Plaines limits a residential shed to 225 square feet and 15 feet tall (never taller than the house), set back at…

Any shed, garden building, workshop or livestock shelter built in unincorporated DuPage County needs a building permit…

In Elgin, a detached shed or accessory building must sit at least 3 feet from an interior lot line and 10 feet from any…

Evanston allows garden sheds in residential rear yards but bans housing birds, poultry (other than hens), or livestock…

In unincorporated Kane County, detached accessory buildings such as sheds are limited to a combined 900 square feet on…

In unincorporated Kankakee County, a detached shed or other accessory building must sit at least ten feet from the…

A garden shed in unincorporated Kendall County can encroach into the side and rear yard setback, but not the front…

In unincorporated Lake County, sheds have no size exemption from building permits. Only playhouses and similar…

Sheds and other accessory buildings in unincorporated Macon County must sit at least ten feet from the house, follow…

In unincorporated Madison County, sheds and other accessory buildings on residential lots are capped at 20 feet tall…

A carport is an accessory structure under the McHenry County UDO. In R-1, R-2 and R-3 residential districts detached…

Every shed, detached garage or other accessory structure in unincorporated McLean County must meet the operational…

Naperville limits detached sheds to 18 feet tall, at least 5 feet from rear and side lot lines, and no more than 25% of…

Detached carports in Oak Lawn are accessory buildings under Village Code and must sit at least 3 feet from the main…

Oak Park exempts small one-story detached tool and storage sheds and playhouses from needing a building permit, but…

Peoria caps residential accessory storage buildings, including sheds, by lot type: a single-family home with an…

A backyard shed in unincorporated Peoria County is capped at the footprint of the house or 1,300 square feet (plus 750…

In unincorporated Rock Island County a shed, detached garage or other accessory building needs a 5-foot setback from…

Sheds and other accessory buildings in unincorporated Sangamon County must sit at least 3 feet from a rear lot line, 6…

Schaumburg caps portable sheds at 25 square feet with no permit needed, fixed sheds in a side yard at 100 square feet…

The Village of Skokie caps accessory buildings and sheds at one story or 15 feet, limits their footprint to 30% of the…

Springfield Zoning Ordinance Section 155.068 allows detached sheds and accessory buildings in the rear yard, requiring…

A one-story storage shed of 120 sq ft or less needs no building permit; 120 to 200 sq ft needs a $25 permit and over…

In unincorporated Tazewell County's residential districts, Section 157.046 caps the combined ground floor area of all…

Tinley Park requires a building permit before erecting a shed, fence, deck or porch, charging a flat $50 fee under the…

Waukegan limits residential sheds to one per lot, 144 square feet in the R1 through R5 districts, placed only in the…

Unincorporated Will County caps accessory buildings at 1,200-3,000 sq. ft. depending on district, allows a 5-foot rear…

Detached sheds and other accessory buildings in Winnebago County are capped at 20 feet tall, must sit 2.5 feet off rear…

Springfield's zoning code bars converting a detached garage or accessory building into a dwelling unit or a business…

Champaign lets a homeowner convert an existing detached garage into an Accessory Dwelling Unit under Sec. 37-628(c)…

Chicago authorizes garage conversions to coach houses (detached ADUs) and conversion units (attic/basement ADUs) under…

Converting a garage to living space in unincorporated Cook County requires a building permit and zoning compliance. The…

A Des Plaines detached garage is capped at 720 square feet and 15 feet tall (never taller than the house) with walls 5…

Evanston lets homeowners convert an existing detached garage or accessory building into a coach-house ADU, and a…

In unincorporated McHenry County you cannot convert a detached garage or other accessory structure into living quarters…

Schaumburg does not recognize tiny houses, accessory dwelling units, or intermodal shipping containers as a lawful…

Waukegan's accessory dwelling unit rule flatly bars axels or wheels on the structure, closing the door on towable tiny…

Elgin permits tiny houses under its One- and Two-Family Dwelling Code, which adopts the 2021 International Residential…

Evanston has adopted Appendix AQ, Tiny Houses, of the 2021 International Residential Code by name under City Code…

Unincorporated McHenry County allows a tiny house as a second unit on a lot only through the zoning code's Ancillary…