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By:  Neva Maxwell, Cook County Planning and Zoning Administrator - December 4, 2025

Cook County Land Services is sharing this update to highlight progress on the new Residential Open Space Overlay (ROSO) Zone District, recap our fall community conversations, and outline next steps as we draft rezone criteria. Many residents have asked thoughtful questions about how and where ROSO may be applied, and we appreciate the engagement so far. 

A Quick Refresher on Zoning in Cook County

Before diving into ROSO, it helps to take a step back and look at zoning in Cook County. Land is divided into “zone districts,” each with requirements that shape the character of an area.

Along Highway 61, for example, you’ll see smaller residential lots mixed with resorts, commercial uses, and some industrial zoning. As you move inland along our County Roads, lot sizes typically shift to 5, 10, or even 20 acres, reflecting the rural feel of the landscape—along with significant amounts of State and Federal public land.

Residents curious about zoning can explore the County’s interactive “Zoning and Land Use Regulations Map” on the Cook County website under “Mapping.”

What the ROSO District Is Designed to Do

In addition to standard zoning, the County can create “overlay districts,” which apply additional regulations in specific areas for a defined purpose. ROSO is one of these overlays and was created to support a permitting pathway that encourages residential development for Cook County residents while preserving open space.

ROSO allows higher residential density when at least 50% of the land is preserved as open space. The district is only eligible in certain areas—generally non-shoreland, near major roads, and within FAR-2 and FAR-3 districts (10- and 5- acre minimum lot sizes, respectively). This approach supports more affordable development by allowing shared driveways, shared septic systems, and more efficient infrastructure, while still respecting Cook County’s rural character.

ROSO is designed to incentivize a type of development known as an “open space subdivision.” These subdivisions cluster homes on smaller lots and preserve half the land—often areas with wetlands, steep slopes, or other natural features that are not ideal for building. To make this approach attractive to property owners, ROSO allows a 2x density bonus. For example, land that would normally allow six residential lots could permit up to twelve. In practice, septic capacity and natural limitations often reduce the actual number of buildable lots and size of homes.

ROSO also follows a two-step process, each step including a public comment and hearing:

1. Rezoning focuses on land use questions like access, compatibility with surrounding development, and proximity to existing infrastructure.
2. Platted Open Space Subdivision (the preliminary plat) addresses detailed design, including natural features, stormwater plans, septic designs, utilities, and lot layout.

As an overlay district, ROSO includes special zoning provisions similar to the Single-Family Residential district along Highway 61, with a few key differences such as: duplexes are permitted, guest houses require a conditional use permit, and vacation rentals are prohibited. These homes must be used as primary or secondary residences or long-term rentals—keeping the focus on year-round housing.

Community Conversations: What We Heard

This fall, Land Services partnered with the Cook County Housing and Redevelopment Authority (HRA) to host community meetings across the county. These sessions included a zoning overview, an introduction to ROSO, and open discussion about opportunities, concerns, and questions.

Attendance varied from meeting to meeting, but each gathering brought valuable perspectives. People asked about everything from the impacts on individual properties to cooperative housing models and subdivision options for families.

A consistent takeaway was the need for criteria to guide decisions about where ROSO is appropriate. This led to the central question: When is a ROSO District rezone suitable, and how will the County determine that?

Themes That Emerged Across the Meetings

Community members shared a range of insights, and several themes rose to the surface:

• Placement and scale: Residents asked how ROSO density might affect road capacity, emergency access, and neighborhood character.
• Conservation-focused design: Many supported the idea of clustering homes to protect open space and preserve sensitive features.
• Clear, predictable criteria: People want transparency and consistency in how ROSO applications are evaluated.
• Balancing new housing development and existing community: Residents recognize the potential to support housing needs, provided it doesn’t negatively affect existing residents.

These discussions helped clarify that eligibility alone does not make a property suitable. Even in areas where ROSO is eligible, the County must consider broader planning implications, safety, access, and community context. 

Next Steps: Developing ROSO Rezone Criteria

Change naturally brings questions, especially when discussing land use and development. With this in mind, the Land Services Department has drafted zoning language to add ROSO-specific suitability criteria for rezoning requests. These new criteria build on the existing rezoning standards—such as consistency with the Land Use Guide Plan and demonstration of public need—by addressing the unique goals and potential impacts of ROSO. 

In summary, the proposed criteria aim to:

• Reinforce the purpose of the ROSO District
• Improve transparency and predictability in the review process
• Ensure rezonings occur only where open space preservation and residential development can successfully coexist

The draft criteria were presented to the Planning Commission on November 12 and will move toward a public hearing in early 2026. The public will have an opportunity to comment during the review process. After the hearing, final recommendations will go to the County Board for consideration.

Meeting notices will be posted on the Cook County website and published in the Cook County News Herald. You can watch recordings of Planning Commission meetings on the County website or contact Planning and Zoning Administrator Neva Maxwell with questions.

Looking Ahead 

Thank you to everyone who participated in our community meetings and shared feedback. Your insights are directly shaping how the ROSO District will be implemented. We look forward to continuing these conversations as the County moves into the next phase of this work.

In the meantime, please reach out to the Land Services Department if you have questions or would like to learn more. We’re always happy to talk about how planning tools—like ROSO—can support community values and thoughtful, balanced growth in Cook County.

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