California's 4th congressional district consists of all of Colusa, Napa, Sutter, and Yuba Counties, and portions of Lake, Placer, Sacramento, Sonoma and Yolo Counties. Cities in the district include American Canyon, Colusa, Cotati, Davis (partial), Esparto, Hidden Valley Lake (partial), Lincoln, Live Oak, Marysville, Middletown, Napa, Petaluma (partial), Rohnert Park, Sonoma, St. Helena, Williams, Winters, Woodland, Wheatland, and Yuba City. It also contains the unincorporated areas of Rio Linda and Elverta in Sacramento, the Capay Valley in Yolo County, and Linda, Olivehurst and Plumas Lake in Yuba County.
