Janesville is a Census-designated place in Coles and Cumberland counties, Illinois, United States. As of the 2020 census, Janesville had a population of 76. Janesville is north of Toledo. Janesville has a post office with the ZIP Code 62435.
Janesville first appeared as a census designated place in the 2020 U.S. census.
It is in the Charleston Community Unit School District 1.