This map is a manually updated version of the habitat map produced by San Francisco Estuary Institute (SFEI) in 2015. SFEI combined several data sources to obtain coverage for the various cover types depicted in the map. The vegetated habitats were based on the Western San Diego County Vegetation dataset, produced in 2012 by San Diego Association of Governments (SANDAG) with a minimum mapping unit (MMU) of 1 hectare (ha) for terrestrial systems and 0.5 ha for wetlands. Developed areas were mapped using the National Land Cover Dataset of 2011 with a MMU of 0.09 ha. Tidal channels and mudflats were based on the Southern California Wetlands Mapping Project from 2005 with a MMU of 0.2 ha. SFEI also conducted supplemental mapping based on aerial imagery from 2008 – 2010 to provide full coverage of the study area. In 2016, Debbie Waldecker from California State Parks (CSP) led a team in a strongly field-based update of the Western San Diego County Vegetation dataset for Border Field State Park, located in the southern portion of the mapping area. This mapping effort was conducted to support decisions regarding a road renovation project within the state park. The MMU was 0.4 ha for the majority of the park, with smaller polygons present in the area along the road. We combined the maps produced by SFEI and CSP and assessed each polygon individually to ensure that a MMU of 0.1 ha was applied consistently across the mapping area. We made exceptions to the MMU for polygons located at the edge of the mapping boundary that were part of larger patches of vegetation not covered by the mapping extent. Image interpretation was based on a combination of sources, including four-band (red, green, blue, NIR) orthoimagery collected in 2016 by Near Earth Observation Systems, LTD (15 cm spatial resolution), 2016 National Aerial Imagery Program four-band orthoimagery (60 cm spatial resolution), 2014 U.S. Geological Survey (USGS) four-band orthoimagery (10 cm spatial resolution), and 2014 USGS lidar point clouds (11 pts/m2). The lidar point clouds were processed to produce a digital elevation model and a canopy height layer. In addition, we conducted extensive ground reference surveys, collecting over 1,800 geotagged photos across the mapping area.