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McHenry County, IL Building Setbacks & Zoning: Structure Height Limits (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

Principal building
35 ft (38 ft in R-3)
Sheds/garages R districts
14 ft flat, 18 ft pitched
Estate/commercial accessory
20 feet
Farm parcel <5 ac
24 feet
Farm parcel 5+ ac
No height limit

Summary

In unincorporated McHenry County, principal buildings in agricultural and residential districts are generally capped at 35 feet (38 feet in R-3). Detached accessory buildings are limited to 14 feet flat or 18 feet pitched in R districts, and 20-24 feet in estate/agricultural districts.

These county ordinances apply to unincorporated areas of McHenry County. Incorporated cities within the county may have their own rules that take precedence over county-level regulations.

In the R-1, R-2, and R-3 Districts, detached accessory structures are limited to fourteen (14) feet in height for a flat or mansard roof design, and eighteen (18) feet in height for a pitched roof design.

View official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2025 S-5: Supplement contains: Local legislation current through Ord. A25-0037, passed 8-19-2025 | State legislation current through ALS 2025 Pamphlet No. 1).

Full Breakdown

UDO Table 16.36-1 sets a maximum building height of 35 feet for most agricultural, estate and residential districts, rising to 38 feet in R-3 and 40 feet in office/industrial districts. Detached accessory structures have their own height rules under § 16.56.050A.2.a: 14 feet for a flat/mansard roof and 18 feet for a pitched roof in R-1/R-2/R-3; 20 feet in E-1 through E-5 and commercial/industrial districts; 24 feet on agricultural parcels under five acres; and no height limit on agricultural parcels of five acres or larger. Attached accessory structures cannot exceed the height of the principal building. Cities set their own height limits.

Violations & Fines

Exceeding the district height limit is a zoning violation requiring a variation from the Zoning Board of Appeals or reconstruction; the county can deny permits and occupancy for over-height structures.

Frequently Asked Questions

How tall can my house be?
In unincorporated McHenry County, most agricultural and residential districts cap principal buildings at 35 feet, with R-3 at 38 feet and office/industrial at 40 feet (Table 16.36-1).
How tall can a detached garage or shed be?
In R-1/R-2/R-3 districts, 14 feet for a flat roof and 18 feet for a pitched roof. Estate and commercial districts allow 20 feet, and large farm parcels have no limit (§ 16.56.050A.2.a).

Sources & Official References

Other rules in McHenry County

All McHenry County rules

Compare McHenry County to another location·View the Illinois building setbacks & zoning overview

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