FEMA National Flood Hazard Layer for Massachusetts

The National Flood Hazard Layer (NFHL) dataset represents the current effective flood risk data for those parts of the country where maps have been modernized by the Federal Emergency Management Agency (FEMA).

The National Flood Hazard Layer (NFHL) dataset represents the current effective flood risk data for those parts of the country where maps have been modernized by the Federal Emergency Management Agency (FEMA). The data in this service was published by FEMA as of July 18, 2025 (Latest Study Effective Date = 07/08/2025; Latest LOMR Effective Date = 07/09/2025). Also see the Map Service and Feature Service. See full details.

MassGIS Data: FEMA National Flood Hazard Layer (NFHL) Full MassGIS metadata: https://www.mass.gov/info-details/massgis-data-fema-national-flood-hazard-layer

Federal Emergency Management Agency (FEMA) National Flood Hazard Layer (effective data only).  Refer to GIS Web Services for the FEMA National Flood Hazard Layer (NFHL) for map service information.  Data is updated as needed.

FEMA Service for current National Flood Hazard Layers For more information, visit: https://hazards.fema.gov/femaportal/wps/portal/NFHLWMS

The National Flood Hazard Layer (NFHL) data incorporates all Flood Insurance Rate Map (FIRM) databases published by the Federal Emergency Management Agency (FEMA), and any Letters of Map Revision (LOMRs) that have been issued against those databases since their publication date. It is updated on a monthly basis. The FIRM Database is the digital, geospatial version of the flood hazard information shown on the published paper FIRMs. The FIRM Database depicts flood risk information and supporting data used to develop the risk data. The primary risk classifications used are the 1-percent-annual-chance flood event, the 0.2-percent-annual-chance flood event, and areas of minimal flood risk. The FIRM Database is derived from Flood Insurance Studies (FISs), previously published FIRMs, flood hazard analyses performed in support of the FISs and FIRMs, and new mapping data, where available. The FISs and FIRMs are published by FEMA. The NFHL is available as State or US Territory data sets. Each State or Territory data set consists of all FIRM Databases and corresponding LOMRs available on the publication date of the data set. The specification for the horizontal control of FIRM Databases is consistent with those required for mapping at a scale of 1:12,000. This file is georeferenced to the Earth's surface using the Geographic Coordinate System (GCS) and North American Datum of 1983.