Kane County, IL Building Setbacks & Zoning: Lot Coverage Limits (2026)
Key Facts
- Lots ≤2 acres
- 900 sq ft accessory combined
- Lots 2–5 acres
- 1,800 sq ft accessory combined
- Max accessory buildings
- Two detached per residence
- Animal housing
- 100 ft from other residence
- Principal coverage
- Per zoning district
Summary
Kane County caps accessory-building coverage by combined floor area: 900 square feet on lots of 2 acres or less and 1,800 square feet on lots of 2 to 5 acres. Overall lot coverage and floor-area ratios for principal buildings are set by the zoning district.
On lots of (2) acres or less, the detached accessory buildings or structures shall not exceed a combined total of (900) square feet in total floor area under roof. On lots greater than (2) acres, but less than (5) acres, the detached buildings or structures shall not exceed a combined total of (1,800) square feet in total floor area under roof.
Full Breakdown
For detached accessory buildings, the county limits total floor area under roof rather than a percentage: on lots of 2 acres or less, all detached accessory buildings combined may not exceed 900 square feet; on lots over 2 but under 5 acres, 1,800 square feet combined, with a maximum of two detached accessory buildings. Agricultural animals must be housed and yarded no closer than 100 feet from any residence other than the owner's. Maximum lot coverage or floor-area ratio for principal buildings is established by the property's zoning district in the Kane County Zoning Ordinance (Chapter 25); confirm the district-specific coverage figure with the Building & Zoning Division.
Violations & Fines
Exceeding the combined accessory floor-area caps or a district's coverage limit is a zoning violation; the county may deny permits or require removal of excess structures.
Frequently Asked Questions
How much accessory building can I put on a 1-acre lot?
Is there a percentage lot-coverage cap?
Sources & Official References
Other rules in Kane County
Compare Kane County to another location·View the Illinois building setbacks & zoning overview
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