High Quality Content by WIKIPEDIA articles! Lewistown is a city in Fulton County, Illinois, United States. The population was 2,522 at the 2000 census. It is the county seat of Fulton County. Located in central Illinois, it is southwest of Peoria. It is the source of Spoon River Anthology by Edgar Lee Masters, who lived there. Native American burial mounds are nearby at Dickson Mounds on Illinois Route 97.