Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Solano, and Sonoma counties. Contra Costa, Humboldt, Lake, Los Angeles, Mendocino, San Mateo, Santa Clara, Solano and Sonoma. Vacaville is a city located in Solano County in Northern California. It consisted of portions of Alameda, Contra Costa, Sacramento, and Solano Counties. In 1837 the Indian Chief Solano received the Rancho Suisun Mexican land grant. Two state prisons are located in Vacaville&colon; California State Prison, Solano and California Medical Facility. It consists of Marin, Napa, Solano and Sonoma counties. It consists of Napa County plus portions of Contra Costa, Lake, Solano, and Sonoma counties. It is older than California State Prison, Solano, the other state prison in Vacaville. Hawk succeeded in getting a change of venue from Sutter County, to Solano County. President Obama declared a major disaster for Napa and Solano counties. The aqueduct delivers water to clients in Napa and Solano counties. Yolo's water allowance under the Solano decree may also be increased. Medflies were found in traps as late as 2007 in Solano County, California. Rafael Solano (portrayed by Justin Baldoni) is former playboy and owner of the Marbella.