Forsyth is a village in Macon County, Illinois, United States. Its population was 3,734 at the 2020 census, up from 3,490 in 2010. It is included in the Decatur, Illinois Metropolitan Statistical Area.

Macon County is a county located in the U.S. state of Illinois. According to the 2020 United States Census, it had a population of 103,998. Its county seat and most populous city is Decatur.