Illinois has 102 counties and 20 congressional districts: 88 counties are wholly within a given congressional district and 14 counties are divided among more than one congressional district.

CDs # 1, # 2, # 3, # 4, # 5, # 7 and # 9 are wholly within Cook County

UNDIVIDED COUNTIES (wholly within one Congressional District):

• CD # 11: Grundy
• CD # 12: Alexander, Jackson, Monroe, Perry, Randolph, St.Clair and Union
• CD # 14: DeKalb, Kane, Kendall and Lee
• CD # 15: Champaign, DeWitt, Douglas, Edgar, Ford, Iroquois, Livingston, Piatt and Vermilion
• CD # 16: Boone, Jo Daviess, McHenry, Stephenson and Winnebago
• CD # 17: Bureau, Carroll, Fulton, Hancock, Henderson, Henry, Knox, McDonough, Mercer, Rock Island, Warren and Whiteside
• CD # 18: Cass, Logan, Marshall, Mason, Menard, Morgan, Peoria, Putnam, Stark, Tazewell and Woodford
• CD # 19: Clark, Clay, Coles, Crawford, Cumberland, Edwards, Effingham, Franklin, Gallatin, Hamilton, Hardin, Jasper, Johnson, Lawrence, Massac, Moultrie, Pope, Pulaski, Richland, Saline, Shelby, Wabash, Wayne and White
• CD # 20: Bond, Brown, Calhoun, Clinton, Fayette, Greene, Jefferson, Jersey, Macoupin, Marion, Montgomery, Pike, Schuyler, Scott and Washington

DIVIDED COUNTIES (split between more than one Congressional District):

• Adams: CDs 17 and 20
• Christian: CDs 19 and 20
• Cook: CDs 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 13
• DuPage: CDs 6, 13 and 14
• Kankakee: CDs 11 and 15
• Lake: CDs 8 and 10
• LaSalle: CDs 11 and 14
• Macon: CDs 18 and 19
• Madison: CDs 12 and 20
• McLean: CDs 15 and 18
• Ogle: CDs 16 and 17
• Sangamon: CDs 18 and 20
• Will: CDs 11 and 13
• Williamson: CDs 12 and 19

In Illinois, the Minor Civil Divisions/County Subdivisions are the Townships (in 85 counties) or Precincts (in 17 counties): the difference between the two is that the Township has local governmental functions while the Precinct does not. There are also three types of Municipalities in Illinois: the city, the village and the incorporated town- but these are all (with the exception of the City of Chicago in Cook County) not separated from the Township or Precinct from which they were created. As a result, cities, villages and incorporated towns (except for the City of Chicago) are not Minor Civil Divisions/County Subdivisions of the first order in the State of Illinois and every place in Illinois (with, again, the exception of Chicago) is part of a Township or Precinct. In the list below of the Minor Civil Divisions/County Subdivisions in those counties divided among more than one Congressional District, only the Township or Precinct is listed (once more, except in the case of the City of Chicago in Cook County)

ADAMS COUNTY:

• CD # 17 includes the Townships of Camp Point, Gilmer, Honey Creek, Houston, Keene, Lima, Mendon, Quincy, Riverside and Ursa
• CD # 20 includes the Townships of Beverly, Burton, Clayton, Columbus, Concord, Fall Creek, Liberty, McKee, Northeast, Payson and Richfield
• Melrose Township is split between CDs 17 and 20

CHRISTIAN COUNTY:

• CD # 19 includes the Townships of Assumption, Locust, May, Mosquito, Pana, Prairieton, Rosamond and Stonington
• CD # 20 includes the Townships of Bear Creek, Buckhart, Greenwood, Johnson, King, Mount Auburn, Ricks, South Fork and Taylorville

COOK COUNTY:

• CD # 3 includes the Townships of Berwyn, Lyons and Stickney
• CD # 5 includes the Township of Norwood Park
• CD # 7 includes the Township of Oak Park
• CD # 8 includes the Townships of Barrington, Hanover, Palatine and Schaumburg
• CD # 9 includes the Township of Niles
• CD # 10 includes the Townships of New Trier and Northfield
• CD # 13 includes the Townships of Lemont and Orland

Bloom Township is split between CDs 2 and 11
Bremen Township is split between CDs 2 and 3
Cicero Township is split between CDs 3 and 4
Elk Grove Township is split between CDs 6 and 8
Maine Township is split between CDs 6 and 9
Palos Township is split between CDs 3 and 13
Proviso Township is split between CDs 4, 6 and 7
Rich Township is split between CDs 2 and 11
Riverside Township is split between CDs 3 and 7
Thornton Township is split between CDs 2 and 11
Wheeling Township is split between CDs 8 and 10
Worth Township is split between CDs 1 and 3

the City of Chicago is divided among CDs 1, 2, 3, 4, 5, 7 and 9

DU PAGE COUNTY:

• CD # 6 includes the Townships of Addison and Bloomingdale
• CD # 13 includes the Townships of Downers Grove, Lisle and Napierville
• CD # 14 includes the Townships of Wayne and Winfield

Milton Township is split between CDs 6, 13 and 14
York Township is split between CDs 6 and 13

KANKAKEE COUNTY:

• CD # 11 includes the Townships of Bourbonnais, Essex, Ganeer, Limestone, Manteno, Momence, Pembroke, Rockville, St. Anne, Salina, Sumner and Yellowhead
• CD # 15 includes Kankakee, Norton, Otto and Pilot

Aroma Township is split between CDs 11 and 15

LAKE COUNTY:

• CD # 8 includes the Townships of Antioch, Avon, Cuba, Ela, Fremont, Grant, Lake Villa, Newport, Warren and Wauconda
• CD # 10 includes the Townships of Benton, Deerfield, Libertyville, Shields, Vernon, Waukegan and West Deerfield

LA SALLE COUNTY:

• CD # 14 includes the Townships of Adams, Earl, Mendota, Meriden and Northville

the remainder of LaSalle County is in CD # 11

MACON COUNTY:

• CD # 18 includes the Townships of Austin, Illini and Niantic

Hickory Point Township is split between CDs 18 and 19
the remainder of Macon County is in CD # 19

MADISON COUNTY:

• CD # 12 includes the Townships of Alton, Chouteau, Nameoki, Venice and Wood River

the remainder of Madison County is in CD # 20

McLEAN COUNTY:

• CD # 18 includes the Townships of Allin, Dale, Danvers, Dry Grove, Funks Grove, Mount Hope and White Oak

Randolph Township is split between CDs 15 and 18
the remainder of McLean County is in CD # 15

OGLE COUNTY:

• CD # 17 includes the Townships of Brookville, Buffalo, Eagle Point, Forreston, Grand Detour, Lincoln, Pine Creek and Woosung

Mount Morris Township is split between CDs 16 and 17
the remainder of Ogle County is in CD # 16

SANGAMON COUNTY:

• CD # 20 includes the Townships of Ball, Capital, Cotton Hill, Divernon and Pawnee

Rochester Township, Springfield Township and Woodside Township are all split between CDs 18 and 20
the remainder of Sangamon County is in CD # 18

WILL COUNTY:

• CD # 13 includes the Townships of DuPage, Homer, Plainfield and Wheatland

Lockport Township and Troy Township are both split between CDs 11 and 13
the remainder of Will County is in CD # 11

WILLIAMSON COUNTY:

• CD # 12 includes the Precincts of Carterville and Grassy

Blairsville Precinct is split between CDs 12 and 19
the remainder of Williamson County is in CD # 19