This polygon shapefile depicts a mask of the nine county San Francisco Bay Area Region, California, onto which other thematic data can be layered. This layer is part of the Conservation Lands Network regional biodiversity GIS database. This dataset was developed/compiled for use in the San Francisco Bay Area Upland Habitat Goals Project, a Project used to identify a Conservation Lands Network (CLN) for biodiversity preservation to inform conservation investments and lasting cooperative conservation partnerships. The Conservation Lands Network GIS Database is the primary output of the Project. The data depicts the spatially explicit CLN that is recommended for the nine county San Francisco Bay Area Region, California. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.