In 2008 the U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC) collected bathymetry and acoustic-backscatter data offshore the Tijuana River Estuary, California. Mapping was conducted as part of the Tijuana Estuary Fine Sediment Fate and Transport Demonstration Project, which was developed by a number of State of California, federal, and private industry partners to provide information about the directions, rates, and processes of fine sediment transport at nearshore settings of California. The primary goal of the Demonstration Project was the monitoring of the transport, fate, and impacts of fine sediment from beach sediment nourishments in 2008 and 2009 near the Tijuana River Estuary, Imperial Beach, California. To achieve this goal, the USGS monitored the water, beach, and seafloor properties near the project site. The coastal mapping provided important baseline bathymetric and seafloor substrate information for the Demonstration Project and was used to develop sampling programs for the Demonstration Project.