Fillmore
- County:
- Ventura County
- County Seat:
- No
- Area (mi²):
- 3.303
- State:
- California
Fillmore is a city located in Ventura County, California. Fillmore has a 2026 population of 17,216. Fillmore is currently growing at a rate of 1.07% annually and its population has increased by 4.32% since the most recent census, which recorded a population of 16,503 in 2020.