The wildland–urban interface (WUI) is the area where houses meet or intermingle with undeveloped wildland vegetation. The WUI is thus a focal area for human–environment conflicts, such as the destruction of homes by wildfires, habitat fragmentation, introduction of exotic species, and biodiversity decline.
Our approach to mapping the WUI is based on an existing WUI definition published in the Federal Register (USDA and USDI 2001), which we applied using a variety of housing density and land cover datasets in a Geographic Information System (GIS) to produce an array of different WUI maps and data products.
No one WUI data set will be sufficient in meeting policy and management needs, but being explicit about WUI mapping approaches, inputs, and goals will further help users weigh different management needs and options.
Types of WUI Datasets

Census-based WUI
WHEN TO USE
If interested in change over time or houses specifically (e.g., evacuation) in the conterminous United States (CONUS)
PRODUCTS
- Block-based (1990-2020)
- Historical Partial Block Group (PBG) based (1940-2020) (coming soon)

Structure-based WUI
WHEN TO USE
If interested in fine-scale information on WUI distribution sub county level in the past decade, and WUI based on all structures (not just housing).
PRODUCTS
- U.S. Building Footprints (Microsoft)
- FEMA Structures (coming soon)
- Google Open Buildings (Global South) (coming soon)

Impervious surface WUI
WHEN TO USE
If interested in large-scale WUI comparisons across regions and countries, and to identify global WUI hotspots.
PRODUCTS
WUI Dataset Comparison Chart
DATASET | CENSUS-BASED | BUILDING-BASED | IMPERVIOUS SURFACE-BASED |
---|---|---|---|
Housing Source | Dicennial Census (polygon) | Building Centroids (point) | Global Human Settlement (raster) |
Land Cover Source | National Land Cover Dataset (NLCD) | National Land Cover Dataset (NLCD) | European Space Agency (ESA) WorldCover |
Spatial Extent | Conterminous U.S. | U.S. and Global South | Global |
Temporal Extent | 1940-2020 (decadal) | 2010s | 2020 |
Pros | Long-term WUI change | Includes all structures (in addtion to housing) | First Global WUI assessment |
Cons | Only housing units – does not include other structures | No WUI change available | No WUI change available |