Vallejo
- County:
- Solano County
- County Seat:
- No
- Area (mi²):
- 30.435
- State:
- California
Vallejo is a city located in Solano County, California. Vallejo has a 2026 population of 123,475. Vallejo is currently growing at a rate of 0.15% annually but its population has decreased by -1.95% since the most recent census, which recorded a population of 125,930 in 2020.