Pecatonica is a village in Winnebago County, Illinois, United States. It is part of the Rockford, Illinois Metropolitan Statistical Area. The population was 2,195 at the 2010 census, up from 1,997 in 2000.

Winnebago County is a county located in the U.S. state of Illinois. According to the 2020 census, it had a population of 285,350 making it the seventh most populous county in Illinois behind Cook County and its five surrounding collar counties. Its county seat is Rockford. Winnebago County is the central county of the Rockford metropolitan area.