Mazon is a village in Mazon Township, Grundy County, Illinois, United States. The population was 1,015 at the 2010 census. The center of population of Illinois is located in Mazon. Illinois' State Fossil, the unique and bizarre Tully Monster was first found in nearby Mazon Creek. Mazon was formerly served by the Santa Fe railway at the Mazon Depot.
As of the census of 2000, there were 904 people, 344 households, and 265 families residing in the village. The population density was 1,510.7 people per square mile (581.7/km²). There were 359 housing units at an average density of 599.9 per square mile (231.0/km²). The racial makeup of the village was 95.58% White, 0.33% African American, 1.22% Native American, 0.11% Asian, 1.22% from other races, and 1.55% from two or more races. Hispanic or Latino of any race were 2.88% of the population.
There were 344 households out of which 38.1% had children under the age of 18 living with them, 62.5% were married couples living together, 10.2% had a female householder with no husband present, and 22.7% were non-families. 18.3% of all households were made up of individuals and 9.0% had someone living alone who was 65 years of age or older. The average household size was 2.63 and the average family size was 2.99.