This polygon shapefile is an index map of bathymetric data available from the 1998 MBARI Monterey Bay Multibeam Survey. Original bathymetric data were collected in 1998 using a 30kHz hull-mounted Simrad EM300 multibeam echo sounder system. This layer is part of the MBARI Monterey Bay Multibeam Survey collection, a compilation of data and imagery of the Monterey Bay and the adjacent seafloor, including coastline, imagery, and bathymetry. This collection of data provides documented layers of of the Monterey Bay to persons/institutions of interest throughout the research and educational communities. These maps help define the geological variability of the seafloor and provide a detailed framework for future oceanographic research, monitoring, and management activities.