Illinois
Buying Land in McHenry County, Illinois
McHenry County, seat Woodstock, sits on the northeastern edge of Illinois, inside the Chicago metropolitan area's fastest-growing exurban fringe -- a region that has lost more farmland to development than any other U.S. metro area since 2001. McHenry County has answered with one of the state's more developed farmland-protection efforts: 11 of Illinois's 40 official agricultural preservation areas sit here, backed by a county conservation-easement commission and a landowner-funded land trust.
Zoning: one Unified Development Ordinance for unincorporated county land
McHenry County consolidated its zoning, subdivision, and related land-use rules into a single Unified Development Ordinance (UDO), effective October 22, 2014, administered by the Planning, Zoning and Land Use Division within the county's Planning & Development Department at 2200 N. Seminary Ave. in Woodstock. The UDO covers zoning districts, subdivisions, planned unit development, conservation design, site-development standards, signs, addressing, earth-extraction (quarrying/gravel) standards, wireless telecommunications, temporary uses, wind-energy systems, and agritourism -- a broader single-document scope than a typical Illinois county zoning ordinance. This authority, under 55 ILCS 5 Division 5-12, applies only in unincorporated McHenry County; land inside any of the county's cities and villages (Crystal Lake, McHenry, Woodstock, Algonquin, and others) falls under that municipality's own zoning ordinance instead.
McHenry County has 17 townships under Illinois's standard township form of county government, not one of the state's 17 commission-form counties. Because the county has adopted the UDO countywide, Article 110 township zoning does not independently apply in any McHenry County township -- the county's Planning, Zoning and Land Use Division is the controlling authority for unincorporated land.
The county's real distinctive: exurban growth pressure, and a real conservation response
McHenry County sits at the edge of the Chicago metropolitan area's fastest-growing exurban fringe, and the pressure this creates on farmland is a documented regional pattern, not a vague impression: since 1970, suburban sprawl has paved over roughly 250,000 acres across the six-county Chicago metro area, reducing farmland's regional share from about 50% to 41% of total land area, and the Chicago-Naperville-Elgin metro area converted more agricultural land to development (92,673 acres between 2001 and 2021) than any other metro area in the country. McHenry County's own western half remains substantially agricultural, but the eastern and central parts of the county have absorbed a real, ongoing share of that regional suburbanization.
What makes McHenry County distinctive isn't just the development pressure -- it's the scale of the county's response. Eleven of Illinois's 40 officially designated agricultural preservation areas are located here, McHenry County farmers have embraced agricultural conservation more actively than in most of the state, and the county maintains its own Agricultural Conservation Easement and Farmland Protection Commission (ACE) specifically to administer permanent farmland-protection easements. See our dedicated conservation-easements page for how this works in practice -- whether you're a farmer considering donating or selling development rights, or a buyer evaluating land that already carries (or sits near) a conservation easement.
Septic, GIS, and other departments to know
Septic (private sewage disposal) permitting in McHenry County runs through the McHenry County Department of Health's Environmental Health Division, which requires any septic system installation, modification, extension, repair, replacement, or abandonment to be performed by an Illinois Department of Public Health-licensed septic contractor. The department holds well and septic permit records dated from February 1, 2003 forward; earlier records may require a different lookup path. Well-siting guidance calls for at least 50 feet of separation from a septic tank and 75 feet from a conventional system's distribution lines.
The McHenry County Assessments office (667 Ware Road, Woodstock) and GIS Department (Suite 206, same address) handle property valuation and parcel mapping, while the County Recorder holds deeds, easements -- including any recorded agricultural conservation easement -- and plats for a specific parcel. University of Illinois Extension serves McHenry County jointly with Lake County.
Who to Call Before Buying Land in McHenry County
Direct WebFetch access to mchenrycountyil.gov was blocked by a network egress restriction throughout this research pass, so several department details reflect search-indexed content rather than a full verbatim read -- confirm current staff, hours, fees, and zoning status directly before relying on this page for a specific parcel.
Planning & Zoning
McHenry County Planning, Zoning and Land Use Division
Zoning verification for unincorporated McHenry County; rezoning, conditional use permits, variations, and subdivision requests under the Unified Development Ordinance.
Building & Permitting
McHenry County Planning & Development -- Building Division
Building permits and septic/well information requests for unincorporated McHenry County.
Environmental Health
McHenry County Department of Health -- Environmental Health
General environmental health questions for McHenry County.
Septic / Onsite Wastewater
McHenry County Department of Health -- Onsite Wastewater Treatment (Septic Systems)
Permits to install, alter, or repair a private sewage disposal system under the statewide IDPH Title 77 Part 905 standard.
GIS / Parcel Records
McHenry County GIS Department
GIS data requests and parcel maps.
Assessor / Property Tax
McHenry County Assessments
Property valuation and assessment records.
Recorder / Clerk / Land Records
McHenry County Recorder
Recorded deeds, easements (including agricultural conservation easements), and plats for a specific parcel.
Agricultural Extension
University of Illinois Extension -- Serving Lake and McHenry Counties
Agricultural land-use, horticulture, and farmland-preservation guidance for McHenry County.
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Sources
- Unified Development Ordinance — McHenry County, Illinois Government (accessed 2026-09)
- Planning, Zoning and Land Use Division — McHenry County, Illinois Government (accessed 2026-09)
- Contact Information -- Planning & Development — McHenry County, Illinois Government (accessed 2026-09)
- Agricultural Land Lost to Development in the Midwest — farmdoc daily (University of Illinois) (accessed 2026-09)
- Illinois — American Farmland Trust (accessed 2026-09)
- Agricultural Conservation Easement and Farmland Protection Commission (ACE) — McHenry County, Illinois Government (accessed 2026-09)
- CHAPTER 2.80: AGRICULTURAL CONSERVATION EASEMENT AND FARMLAND PROTECTION COMMISSION — American Legal Publishing (McHenry County Code) (accessed 2026-09)
- The Land Conservancy of McHenry County receives $135,000 grant — AgriNews (accessed 2026-09)
- Conservation Easements -- The Land Conservancy of McHenry County — The Land Conservancy of McHenry County (accessed 2026-09)
- McHenry County Conservation District — Wikipedia (accessed 2026-09)
- Onsite Wastewater Treatment Systems (Septic Systems) — McHenry County, Illinois Government (accessed 2026-09)
- Assessments -- McHenry County, IL — McHenry County, Illinois Government (accessed 2026-09)
- Find Our Office | Serving Lake and McHenry Counties — University of Illinois Extension (accessed 2026-09)
Last reviewed 2026-09