The Cook County, Illinois general election was held on November 4, 1986. Primaries were held March 18, 1986. Elections were held for the offices of Assessor, Clerk, Sheriff, State's Attorney, Superintendent of Education Service Region, Treasurer, President of the Cook County Board of Commissioners, all 17 seats of the Cook County Board of Commissioners, both seats of the Cook County Board of Appeals, 3 seats on the Water Reclamation District Board, and judgeships on the Circuit Court of Cook County.