A historical survey of US bathymetric mapping is presented up through the major mapping project begun in response to the 1983, establishment of an Exclusive Economic Zone (EEZ), 200 nautical miles seaward. The EEZ extends sovereign rights for the purposes of exploring, exploiting, conserving, and managing natural resources in the coastal ocean. This new area is approximately 3. 4 million square nautical miles or about 1. 3 times the total US land area. To characterize the resources within it, the US National Oceanic and Atmospheric Administration (NOAA) and the US Geological Survey (USGS) are undertaking systematic mapping programs of the EEZ. NOAA's effort includes detailed bathymetric mapping of the seabed. The USGS is using a wide-swath side-scan sonar system to map the EEZ seafloor on a reconaissance scale.