Carrier Mills, Illinois - Wikipedia. Carrier Mills, formerly Carrier's Mills and Morrilsville, also known as Catskin, is a village in Saline County, Illinois, United States.The population was 1,655 at the 2010 census.Carrier Mills was named after George Washington Carrier's saw and grist mills, and was one of the early Cairo and Vincennes Railroad boomtowns.Founded as a mill town, and then a ...