Marion is located in Williamson County. About 16,855 people live here (as of 2020). Between 2010 and 2020, the population declined from 17,193 to 16,855. The region is at 158 meters above sea level. The area covers about 43.2 square kilometers. There are about 1.056 streets in Marion. The region was founded in 1839. The postal codes are 62959. The dialing code is 618. Marion is city in and the county seat of Williamson County, Illinois, United States. Among other things, Marion has restaurants, cafés, schools, banks, hairdressers and pharmacies. More information at
www.cityofmarionil.gov.