Rockford is a city in Winnebago County, Illinois, United States, located on the Rock River. It is the county seat of Winnebago County. The population was 150,115 at the 2010 census, making it the third largest city in Illinois after Chicago and Aurora. Rockford is the largest city in Illinois outside of the Chicago metropolitan area.
Rockford was founded on June 5, 1834 by John Winnebago, a Sauk warrior and Chief of the Winnebago tribe. The city was named after the Rock River, which bisects the city.
Rockford grew rapidly during the 1830s and 1840s. In 1837, the city became the county seat of Winnebago County. By 1838, it had a population of 1,000. The city was connected by stagecoach to Chicago in 1839. In 1841, the city had a population of 2,500.
The Rock