Dixon is a city and county seat of Lee County, Illinois, United States. The population was 15,733 as of the 2010 census, down from 15,941 in 2000. The city is named after founder John Dixon, who operated a rope ferry service across Rock River, which runs through the city. The Illinois General Assembly designated Dixon as "Petunia Capital of Illinois" in 1999 and "The Catfish Capital of Illinois" in 2009.