This polygon shapefile contains annexations in San Joaquin County, California. Annexation is a process by which a municipality expands its boundaries into adjacent areas not already incorporated into the municipality.This layer is part of a collection of GIS data for San Joaquin County in California. This dataset is intended for researchers, students, and policy makers for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production, or to provide a basemap to support graphical overlays and analysis with other spatial data. San Joaquin County (Calif.). Community Development Department. (2015). Annexations, San Joaquin County, California, 2015. San Joaquin County Community Development Department. Available at: http://purl.stanford.edu/rm469xg7582. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.