Forreston is a village in Ogle County, Illinois, United States. The population was 1,446 at the 2010 census, down from 1,469 at the 2000 census.
Forreston is located at 42°7′33″N 89°34′48″W / 42.12583°N 89.58°W / 42.12583; -89.58 (42.125700, -89.579955).
According to the United States Census Bureau, the village has a total area of 2.1 square miles (5 km²), all of it land. It is 100 miles West of Chicago, Illinois