The 3rd District spans the Golden Gate Bridge, connecting high income areas of the North Bay with the eastern portions of the City and County of San Francisco.
The North Bay portion includes the entirety of Marin County, and part of Sonoma County. The cities of Petaluma and Rohnert Park as well as most of the area surrounding the city of Santa Rosa is in the 3rd district, as are the CDPs of Boyes Hot Springs, Eldridge, El Verano, Larkfield-Wikiup, and Temelec.
The San Francisco portion includes the downtown area, as well as all of most of the Marina, Presidio, Nob Hill, Russian Hill, Chinatown, Castro, Haight-Ashbury, Mission, Market, Potrero, Hunter's Point, Bay View, Miraloma Park, and Treasure Island.