Vacaville
- County:
- Solano County
- County Seat:
- No
- Area (mi²):
- 29.87
- State:
- California
Vacaville is a city located in Solano County, California. Vacaville has a 2026 population of 103,994. Vacaville is currently growing at a rate of 1.13% annually and its population has increased by 1.81% since the most recent census, which recorded a population of 102,147 in 2020.