Iroquois County was named for the Iroquois River, which was named after the Iroquois Tribe. According to the 2017 Census of Agriculture, there were 1,516 farms in Iroquois County, spanning 681,289 acres, with an average farm size of 449 acres. Based on land area, Iroquois County is the third-largest county in Illinois. The population of Iroquois County was 29,718 (based on 2010 census). Iroquois County’s temperatures range from 14°F during January to 84°F during July. Average monthly precipitation ranges from 1.61" during February to 4.62" during June. If you're looking for land for sale in Iroquois County, IL, check out Land Pro LLC's current listings below. If there are no current listings in Iroquois County, take a look at land for sale in neighboring Ford County, Kankakee County, and Vermilion County. You can also view all the Illinois land offered for sale by Land Pro LLC.