Ontario is a city located in San Bernardino County, California, United States. As of the 2000 Census, the city had a total population of 170,373. It is the home of LA/Ontario International Airport and the Ontario Mills. It is also the former home of the Ontario Motor Speedway. It takes its name from the Ontario Model Colony development established in 1882 by the Canadian engineer George Chaffey and his brothers William Chaffey and Charles Chaffey. They named the settlement after their home province of Ontario, Canada.