Sources

Two federal datasets, plus Census geography files for the crosswalk.

FEMA National Risk Index

Composite risk and eighteen hazard ratings at county and census tract grain. Retrieved from FEMA’s ArcGIS organisation. Version December 2025. Refreshed when FEMA publishes a new version, approximately annually.

Attribution: Source: FEMA National Risk Index, December 2025. The Risk Index is intended for planning purposes only and is not a substitute for localised risk assessment.

US Census American Community Survey

Five-year estimates for the 2020–2024 window: tables B25103 (median real estate taxes paid), B25077 (median home value), and B01003 (population), published at ZCTA grain. Refreshed annually when the Census Bureau releases a new five-year file.

Attribution: Source: US Census Bureau, American Community Survey 5-Year Estimates 2020–2024.

Census geography

The 2020 ZCTA-to-tract relationship file and the 2020 Gazetteer internal points, used for the crosswalk and for finding nearby ZIP codes. For Connecticut, the 2022 county subdivision relationship files.

Not used

First Street and Risk Factor are licensed and their terms bar redistribution; we do not use or scrape them. No home-insurance premium data is used, because no free authoritative source exists. USFS Wildfire Risk to Communities was evaluated and dropped: the tabular product is not retrievable from our build network and the NRI already publishes a wildfire rating on the same row as every other hazard.