Thomson is a village along Illinois Route 84 near the Mississippi River in Carroll County, Illinois, United States. The population was 590 at the 2010 census, up from 559 at the 2000 census. Just north of the village is the United States Penitentiary, Thomson, a mostly-unused former state prison, purchased by the Federal Bureau of Prisons in 2012. Currently USP Thomson houses over 100 low-security inmates as it remodels to federal maximum-security standards.

Carroll County is a county located in the U.S. state of Illinois. As of the 2020 census, the population was 15,702. Its county seat is Mount Carroll.