Oxford is a city in northwestern Butler County, Ohio, United States, in the southwestern portion of the state. It lies in Oxford Township, originally called the College Township. The population was 21,943 at the 2000 census. This college town was founded as a home for Miami University. Oxford is served by U.S. Route 27, Ohio State Route 732, and Ohio State Route 73. There were 5,870 households out of which 16.5% had children under the age of 18 living with them, 26.8% were married couples living together, 6.4% had a female householder with no husband present, and 64.8% were non-families. 32.0% of all households were made up of individuals and 5.5% had someone living alone who was 65 years of age or older. The average household size was 2.43 and the average family size was 2.85.