Statewide polygon feature class of 100 and 500 year flood zones for unincorporated areas of Illinois as indicated on Federal Emergency Management Agency (FEMA) National Flood Insuranc Program (FIRM) maps and Flood Hazard Boundary maps. ISWS.FileengIllinois Geospatial Data ClearinghousePublicFlood Zones for Unincorporated Areas, One-Hundred and Five-Hundred Year [Illinois]Datasets