New Hampshire Zoning Atlas

The New Hampshire Zoning Atlas is a database and interactive online map cataloguing and portraying zoning district-level land use regulations affecting housing construction across the entire land area of the state. The data are valid as of June 1, 2024 and represent the zoning and other land use regulations that local governments have adopted in their own ordinances, and in some cases, the ways in which state law interacts with those provisions. The data are available to download so that users can reproduce their own maps, analyze the data statistically, and integrate the datasets with information from other sources or states. Below, the background and basic methodology for the Atlas is presented, followed by some of the major findings illustrated with static maps, and finally an interactive version of the Atlas for deeper exploration is available within this summary. A link to the full NH Zoning Atlas is also provided, as well as a tutorial on how to use the NH Zoning Atlas.

New Hampshire has 228 jurisdictions with independent zoning authority. 215 of these jurisdictions are municipalities, but 10 are submunicipal and village governments, and one (Coös) is a county with zoning authority for 23 unincorporated areas within its territory. There are also two unincorporated places without zoning. The goal of the NH Zoning Atlas is to compile the regulations of all of these authorities into a comprehensive statewide dataset. In total, there are 269 jurisdictions in the dataset: every municipal and submunicipal zoning authority mentioned above, plus 19 towns without zoning.

There are two datasets. The first, a Google spreadsheet, contains the "raw data" found in local ordinances, including textual descriptions of complex rules that could not be summarized with a single number without some loss of information, and covers all zoning districts in the state, including unmapped districts. The second dataset, available in comma-separated values (csv) format, covers only mapped districts, includes state legal provisions that in some cases override local zoning rules inconsistent with state law, and interprets complex rules as numerical codes suitable for statistical analysis and filtering operations in the map. It also removes base districts that are wholly contained within overlay districts to avoid double-counting. The second dataset links up to the attribute table in the ArcGIS feature class for the state. These datasets are accessible  here .

Throughout the summer of 2022 zoning codes from across the state were collected and synthesized to create a single spreadsheet cataloging every single zoning district (base and overlay). This spreadsheet contains basic information such as the name and abbreviation for each district, whether the district is an overlay, and the primary purpose of the district (residential, mixed use, or non-residential). In addition to this basic information multiple characteristics were coded into the spreadsheet regarding treatment of different housing types, dimensional requirements, parking requirements, affordable or elderly housing requirements, and other considerations. During the summer and fall of 2023 amendments to zoning codes, which were approved between June 1, 2022 and June 1, 2023 were reviewed and the spreadsheet was updated to reflect the current regulations.

Concurrent to the collating of the codes, geographic information systems (GIS) data was collected for each jurisdiction, where available. These GIS files, along with dozens newly created for this project by digitizing print versions of zoning maps, were merged into a single statewide GIS feature layer. This GIS layer was then joined with a modified version of the zoning attribute table. Finally areas considered to be non-developable due to permanent protection status or the presence of 10 or more contiguous acres of water and/or wetlands were clipped out of the statewide zoning layer. This resulting layer allows for the visualization and analysis of the "buildable" areas , which is approximately 61% of the state.

For a more detailed overview of the methodology refer to the The New Hampshire Zoning Atlas paper found on the  NH Zoning Atlas home page , or linked  here . The paper also details many findings from studying the NH Zoning Atlas, several of which are summarized below.

While the statewide analysis provides a broad overview of the nature of housing regulations across New Hampshire, we wanted to examine regulations at a regional level. We chose to focus on the state's largest metropolitan area: the City of Manchester and the adjacent seven towns of Auburn, Bedford, Goffstown, Hooksett, Litchfield, Londonderry and Merrimack. Specifically we looked at available parcels for development based on both the zoning regulations and the available build-out potential of the over 70,000 parcels within the eight community region. Note this analysis was completed using the 2022 Atlas data.

This map shows the zoning districts, less non-buildable areas, for the entire State of New Hampshire. Clicking on the map will bring up information for each jurisdiction and the underlying zoning district. Use the arrows in the corner of the pop-up window to cycle between the jurisdiction data and the zoning district(s) data. For the ability to filter the data shown on the map you can view the full NH Zoning Atlas interactive mapping application  here .

A brief tutorial on using the NH Zoning Atlas is  available here .

Data collected for the NH Zoning Atlas suggest that there is much that we can do to adjust our zoning and help our communities be more welcoming to a modest increase in housing. Changes to zoning will help communities remain vibrant and assist our state in attracting and retaining young people, growing families, aging seniors, and a strong workforce for our economy.

The New Hampshire Zoning Atlas does not take a position in the debate between those who advocate for local control, and those who argue for stronger state limits on local governance. We simply encourage policy-makers at the local and state levels to discuss possible changes in zoning, both small and large, that can help ease the housing shortage and strengthen our communities. How those changes take place is for others to decide.

A variety of changes can and should be discussed, including appropriate reductions in minimum lot sizes for single-family and multi-family housing, front setback requirements, and parking requirements, perhaps especially for ADU’s.

At present, the plan is to update the atlas annually with data valid as of June 1st of each year, and to maintain a consistent time series for research purposes. The New Hampshire Zoning Atlas will remain an integral part of the  National Zoning Atlas  and will continue to provide critical information on the formal legal treatment of housing development in the Granite State. Visit the NH Zoning Atlas page ( NHZoningAtlas.org ) for the most up-to-date information.