The West Valley Mosquito and Vector Control District is a special District that was formed in 1983 in response to the needs of the residents of the West Valley area for the reduction of mosquitoes plaguing the community. In 1985 the District expanded its surveillance and control activities to include flies, rodents, stinging insects, and various other medically important vectors capable of transmitting disease or causing human discomfort. In 1998 the District changed its name from West Valley Vector Control District to West Valley Mosquito and Vector Control District.

The District's boundaries include the cities of Chino, Chino Hills, Montclair, Ontario, Rancho Cucamonga and unincorporated county areas. The District serves over 520,000 residents in 200 square miles of the West Valley.

Governing power is vested in a six-member Board of Trustees. One member each is appointed by the City Councils of Chino, Chino Hills, Montclair, Ontario and rancho Cucamonga with the remaining board member being appointed by the San Bernardino County Board of Supervisors.