All or parts of Addison, Arlington Heights, Barrington Hills, Bloomingdale, Carol Stream, Carpentersville, East Dundee, Elgin, Elk Grove Village, Glendale Heights, Hanover Park, Hoffman Estates, Lombard, Palatine, Rolling Meadows, Roselle, Schaumburg, South Elgin, Streamwood, Villa Park and Wood Dale are included.

The 8th district takes in the communities of Bloomingdale, Schaumburg (shared with Cook County), Roselle, and Itasca; most of Carol Stream; the majority of Elk Grove Village west of Tome Rd (shared with DuPage County); part of Hanover Park (shared with Cook County); eastern Bartlett; western Wood Dale; northwestern Addison; part of Glen Ellyn; and part of northern Glendale Heights.

They are partitioned by Illinois Highway 47, Regency Parkway, Farm Hill Dr, Del Webb Blvd, Jane Adams Memorial Tollway, Sandwald Rd, Ridgecrest Dr, Brier Hill Rd/Illinois Highway 47, Coombs Rd, Shadow Hill Dr, Campton Hills Dr, West Main St, South Tyler Rd, Division St, Fox River, North Washington Ave, Douglas Rd, Orion Rd, and East Fabyan Parkway.

The 8th district takes in the communities of East Dundee (shared with Cook County), West Dundee, Carpentersville, Sleepy Hollow, South Elgin, Gilberts, Pingree Grove; most of Elgin (shared with Cook County); half of St. Charles; southern Algonquin; western Wayne and Barrington Hills; eastern Hampshire; southeastern Huntley; a portion of Geneva east of the Fox River; and part of Batavia.

[6] Democrat Raja Krishnamoorthi of Hoffman Estates announced his candidacy for the seat in late May 2011.