Abingdon is a city in Knox County, Illinois, United States, 50 miles (80 km) west of Peoria. It is part of the Galesburg Micropolitan Statistical Area. The city was first settled in 1828 and was incorporated in 1857. In june of 1907, the patent for the common spring-loaded mousetrap was awarded to William Hooker William Armstrong and Knox Mark of Abingdon. The population was 3,319 at the 2010 census, down from 3,612 at the 2000 census.

Knox County is a county in the U.S. state of Illinois. According to the 2020 census, it had a population of 49,967. Its county seat is Galesburg.