Iroquois County, Illinois is located in East-Central Illinois along the Indiana border, 80 miles south of Chicago and 30 miles north of Champaign-Urbana. It is the third largest county in Illinois in area (1122 square miles, 35 miles north and south and 32 miles east and west). Forty miles of Interstate Highway 57 bisect the county from north to south, and US Routes 24 and 45 cross at Gilman.