Fairfield
- County:
- Solano County
- County Seat:
- Yes
- Area (mi²):
- 41.586
- State:
- California
Fairfield is a city located in Solano County, California. Fairfield has a 2026 population of 122,646. It is also the county seat of Solano County. Fairfield is currently growing at a rate of 1.26% annually and its population has increased by 2.3% since the most recent census, which recorded a population of 119,890 in 2020.