Cisco is a village in Piatt County, Illinois, United States. The population was 264 at the 2000 census. According to the 2010 census, Cisco has a total area of 0.37 square miles, all land. There were 109 households, out of which 28.4% had children under the age of 18 living with them, 72.5% were married couples living together, 5.5% had a female householdeā¦Cisco is a village in Piatt County, Illinois, United States. The population was 264 at the 2000 census. According to the 2010 census, Cisco has a total area of 0.37 square miles, all land. There were 109 households, out of which 28.4% had children under the age of 18 living with them, 72.5% were married couples living together, 5.5% had a female householder with no husband present, and 21.1% were non-families. 20.2% of all households were made up of individuals, and 7.3% had someone living alone who was 65 years of age or older. The average household size was 2.42 and the average family size was 2.78.