The National Zoning Atlas is a groundbreaking initiative that maps and interprets land use regulations for more than 33,000 jurisdictions across the United States. Drawing from tens of thousands of zoning codes and detailed geospatial analysis, the Atlas provides clarity on complex zoning rules that shape how communities grow and develop. Designed for use by advocates, planners, researchers, and the public, it transforms zoning from a bureaucratic barrier into a tool for crafting better housing, sustainable environments, and equitable communities.
What Is the National Zoning Atlas?
Origins and Leadership
Launched by Cornell University Professor Sara Bronin and her team in 2022, the National Zoning Atlas (NZA) builds upon earlier state-level atlases like the Connecticut Zoning Atlas.
Mission and Goals
The NZA strives to digitize, demystify, and democratize zoning regulations. Its mission is to make zoning data actionable so that housing advocates, policy makers, and local governments can identify reforms that support affordable housing, environmental resilience, economic vitality, and social equity.
How It Works: Methodology and Data
Four-Step Workflow
- Identify jurisdictions with zoning authority (cities, counties, towns).
- Extract zoning districts from official texts and maps.
- Analyze and digitize zoning regulations: who can build what, where, and under which conditions.
- Merge text and map data, perform quality control, and publish interactive results.
Scope and Coverage
To date, the Atlas includes over 7,000 jurisdictions, representing extraction of 765,000 pages of code. It unpacks more than 200 characteristics per zoning district covering land use, density, lot size, parking, building height, and rules for accessory dwelling units.
What Users Can Do with the NZA
Interactive Map and Tools
The public site features an interactive map with filters to display where single-family homes, multi-family buildings, accessory dwellings, or parking mandates are permitted as-of-right. Users can zoom to their city, county, or metro area and generate Zoning Snapshots that summarize local rules.
Detailed Analysis
Supporting research tools provide deeper insights, such as how minimum lot sizes and ADU rules correlate with housing affordability and school access. For example, New England organizations used NZA data to show that 43 percent of zoned land requires large lots limiting density and inflating housing costs.
Impact and Real-World Uses
Informing Reform Efforts
Advocates in Colorado, New Hampshire, Rhode Island, and Virginia have cited NZA findings to support legislation easing zoning restrictions, including reducing minimum lot sizes and parking mandates, or allowing missing-middle housing.
Policymaker Engagement
Planners and officials utilize the Atlas to benchmark their jurisdictions, compare land use outcomes, and design data-driven zoning reforms. Tools like Realtor.com leverage NZA data in statewide scorecards ranking affordability and zoning friendliness.
Transparency and Advocacy
By providing clear snapshots and straightforward visualizations, the NZA empowers communities. Neighborhood groups, local press, and researchers can highlight how land-use rules shape housing access, climate resilience, and economic opportunity.
Challenges and Considerations
Complexity of Zoning Data
Local zoning codes often include overlapping districts and vague rules. The NZA team uses a careful flattening method: they merge overlays and base zones, keeping the most restrictive rules when conflicts arise.
Manual Labor and Future Automation
Despite early experiments with machine learning, the NZA prioritizes accurate manual reading and digitization, as current algorithms struggle with nuanced legal texts.
Coverage Gaps and Updates
Some jurisdictions lack available zoning data, and others are in progress. As local codes evolve, the NZA updates maps and snapshots, ensuring its coverage remains relevant.
Future Directions
Scaling Nationally
The NZA team continues expanding, aiming to include 30,000 jurisdictions. They seek funding via grants and partnerships to boost digital coverage and automation.
Enhanced Policy Tools
Plans include enriching story maps, regional comparisons, and interactive dashboards that tie zoning data to demographics, transit, climate resilience, and land inequality.
Why Zoning Matters
Housing Affordability and Equity
Zoning regulations often lock in low-density, single-family-only policies that limit housing options and drive up prices. Accessory dwelling units, duplexes, and higher density are frequently restricted making homes more expensive and less accessible, especially near schools or transit hubs.
Environmental and Economic Sustainability
Restrictive zoning patterns contribute to sprawl, long commutes, car dependency, and infrastructure strain. Reforming zoning is a key part of building equitable neighborhoods, reducing emissions, and strengthening local economies.
The National Zoning Atlas is revolutionizing how Americans understand and engage with local land-use rules. By converting opaque zoning codes into clear, interactive data, it empowers citizens, planners, and policymakers to tackle housing shortages, curb sprawl, and promote inclusive development. While challenges remain in coverage and automation, the Atlas offers a powerful model for transparent governance and evidence-based reform. As zoning continues to shape our built environment, the NZA stands as a vital tool for shaping healthier, more connected communities across the country.
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