FEMA began its flood mapping efforts with the first generation of flood maps called Flood Hazard Boundary Maps (FHBM). These were the first flood maps issued, and they were based on approximate flood hazard data. They provided general indications of where the Special Flood Hazard Areas (SFHA) were within a community.

Today, FHBMs are generally used in communities new to the National Flood Insurance Program (NFIP) that are participating in the entry-level Emergency Program phase. In other communities, FHBMs have been replaced by Flood Insurance Rate Maps (FIRM).