FEMA Flood Zone Data: Working with FIPS Geography

FEMA's flood hazard and insurance data products use a combination of FIPS codes and FEMA-specific community identifiers. The National Flood Insurance Program (NFIP) tracks policies and claims at the ZIP code and county level; the National Flood Hazard Layer (NFHL) — the spatial database of Flood Insurance Rate Maps (FIRMs) — uses a community identifier system that ultimately ties back to county FIPS codes. Understanding both systems is necessary for geographic flood risk analysis.

In FEMA's NFIP policy and claims data (available via OpenFEMA), each record includes a county FIPS code field that uses the standard 5-digit format, making it directly joinable to Census and BLS data. Researchers studying the relationship between flood risk, insurance coverage, and socioeconomic vulnerability routinely join NFIP data with ACS demographic estimates using county FIPS as the key. For coastal counties like Los Angeles (06037) or high-risk Gulf Coast counties, this dataset is particularly rich.

FEMA's community identifiers are a separate system used in the FIRM panels and the Community Rating System (CRS). A community identifier is a 6-digit code (state FIPS + 4-digit community number) that corresponds to the local government responsible for floodplain management — typically a county or incorporated municipality. Counties that have subdivisions (cities and towns) may have multiple community identifiers within the same FIPS code area.

For county-level flood risk analysis, the most useful FEMA data products are the NFIP summary statistics (policies in force, claims paid, repetitive loss properties) aggregated by county, and the National Risk Index — FEMA's composite measure of natural hazard risk that includes Expected Annual Loss estimates for 18 natural hazard types at the county level. Both are published by county FIPS code. Use our county FIPS reference to identify codes for your study area.