Solano County, California, USA

Solano County lies between the San Francisco Bay Area and the Sacramento Valley, with Fairfield as its county seat and Vallejo, Vacaville and Suisun City among its principal communities. Its landscape reaches from the shores of San Pablo and Suisun bays across the vast Suisun Marsh to rolling valleys, oak woodlands and productive farmland. The area is part of the traditional homeland of Patwin people, and Solano became one of California’s original counties in 1850 after periods of Spanish and Mexican rule. The county had about 455,400 residents in 2025. Agriculture, food and beverage production, biotechnology, manufacturing, logistics, health care, tourism and the presence of Travis Air Force Base shape its economy.