Fillmore is a city in
Ventura County,
California,
United States in the
Santa Clara River Valley. In an agriculture area with rich, fertile soil, Fillmore has a historic downtown that was established when Southern Pacific built the railroad through the valley in 1887. They also provided a name for the town; J. A. Fillmore was a general superintendent for the company's Pacific system. The population was 15,002 at the
2010 census, up from 13,643 at the
2000 census.