: http://www.ci.rockford.il.us Rockford is a mid-sized city located on both banks of the Rock River in far northern Illinois. Often referred to as "The Forest City", Rockford is the county seat of Winnebago County, Illinois, USA. As reported in the 2010 U.S. census, the city was home to 152,871 people. The metropolitan area has 320,204 residents as of the 2000 census. During the latter half of the 20th century Rockford was the second largest city in Illinois and is currently the most populated city in Illinois outside of the Chicago Metropolitan Area. The current mayor is Lawrence J. Morrissey, an independent re-elected to a second four-year term in April 2009.