| Adams County | 5 | 8,717 | Quincy SD 172, Central CUSD 3, CUSD 4, Liberty CUSD 2, Payson CUSD 1 |
| Alexander County | 2 | 582 | Egyptian CUSD 5, Cairo USD 1 |
| Bond County | 2 | 1,852 | Bond County CUSD 2, Mulberry Grove CUSD 1 |
| Boone County | 2 | 8,993 | Belvidere CUSD 100, North Boone CUSD 200 |
| Brown County | 1 | 673 | Brown County CUSD 1 |
| Bureau County | 12 | 4,410 | All 12 Bureau County districts → |
| Calhoun County | 2 | 616 | Calhoun CUSD 40, Brussels CUSD 42 |
| Carroll County | 3 | 1,945 | West Carroll CUSD 314, Eastland CUSD 308, Chadwick-Milledgeville CUSD 399 |
| Cass County | 3 | 2,181 | Beardstown CUSD 15, Virginia CUSD 64, A-C Central CUSD 262 |
| Champaign County | 15 | 25,458 | All 15 Champaign County districts → |
| Christian County | 6 | 4,860 | Taylorville CUSD 3, Pana CUSD 8, Central A & M CUD 21, Morrisonville CUSD 1, South Fork SD 14, Edinburg CUSD 4 |
| Clark County | 3 | 2,456 | Marshall CUSD 2C, Casey-Westfield CUSD 4C, Martinsville CUSD 3C |
| Clay County | 3 | 2,130 | Flora CUSD 35, North Clay CUSD 25, Clay City CUSD 10 |
| Clinton County | 12 | 5,008 | All 12 Clinton County districts → |
| Coles County | 3 | 5,973 | Mattoon CUSD 2, Charleston CUSD 1, Oakland CUSD 5 |
| Cook County | 144 | 682,868 | All 144 Cook County districts → |
| Crawford County | 4 | 2,684 | Robinson CUSD 2, Oblong CUSD 4, Palestine CUSD 3, Hutsonville CUSD 1 |
| Cumberland County | 2 | 1,493 | Cumberland CUSD 77, Neoga CUSD 3 |
| De Witt County | 2 | 2,417 | Clinton CUSD 15, Blue Ridge CUSD 18 |
| DeKalb County | 8 | 16,544 | DeKalb CUSD 428, Sycamore CUSD 427, Sandwich CUSD 430, Genoa Kingston CUSD 424, Somonauk CUSD 432, Indian Creek CUSD 425, Hinckley Big Rock CUSD 429, Hiawatha CUSD 426 |
| Douglas County | 4 | 3,137 | Arthur CUSD 305, Tuscola CUSD 301, Arcola CUSD 306, Villa Grove CUSD 302 |
| DuPage County | 42 | 143,955 | All 42 DuPage County districts → |
| Edgar County | 6 | 2,650 | Paris-Union SD 95, Paris CUSD 4, Shiloh CUSD 1, Edgar County CUD 6, Kansas CUSD 3, Paris Cooperative High School |
| Edwards County | 1 | 821 | Edwards County CUSD 1 |
| Effingham County | 5 | 5,063 | Effingham CUSD 40, Teutopolis CUSD 50, Altamont CUSD 10, Dieterich CUSD 30, Beecher City CUSD 20 |
| Fayette County | 4 | 2,675 | Vandalia CUSD 203, Brownstown CUSD 201, Ramsey CUSD 204, St Elmo CUSD 202 |
| Ford County | 3 | 2,548 | Paxton-Buckley-Loda CUD 10, Gibson City-Melvin-Sibley CUSD 5, Tri Point CUSD 6-J |
| Franklin County | 9 | 5,523 | Frankfort CUSD 168, Benton CCSD 47, Christopher USD 99, Benton Cons HSD 103, Sesser-Valier CUSD 196, Zeigler-Royalton CUSD 188, Thompsonville CUSD 174, Ewing Northern CCSD 115, Akin CCSD 91 |
| Fulton County | 6 | 3,908 | Canton Union SD 66, Lewistown CUSD 97, CUSD 3 Fulton County, V I T CUSD 2, Astoria CUSD 1, Spoon River Valley CUSD 4 |
| Gallatin County | 1 | 703 | Gallatin CUSD 7 |
| Greene County | 3 | 1,703 | North Greene CUSD 3, Carrollton CUSD 1, Greenfield CUSD 10 |
| Grundy County | 12 | 13,098 | All 12 Grundy County districts → |
| Hamilton County | 1 | 1,091 | Hamilton Co CUSD 10 |
| Hancock County | 8 | 2,703 | Hamilton CCSD 328, Southeastern CUSD 337, Carthage ESD 317, Warsaw CUSD 316, Illini West H S Dist 307, Nauvoo-Colusa CUSD 325, La Harpe CSD 347, Dallas ESD 327 |
| Hardin County | 1 | 498 | Hardin County CUSD 1 |
| Henderson County | 1 | 752 | West Central CUSD 235 |
| Henry County | 9 | 7,860 | Geneseo CUSD 228, Kewanee CUSD 229, Orion CUSD 223, Wethersfield CUSD 230, Galva CUSD 224, Cambridge CUSD 227, Colona SD 190, AlWood CUSD 225, Annawan CUSD 226 |
| Iroquois County | 7 | 3,909 | Central CUSD 4, Iroquois County CUSD 9, Iroquois West CUSD 10, Milford Area Public Schools District 124, Donovan CUSD 3, Cissna Park CUSD 6, Crescent Iroquois CUSD 249 |
| Jackson County | 8 | 6,811 | Murphysboro CUSD 186, Carbondale ESD 95, Carbondale CHSD 165, Trico CUSD 176, Unity Point CCSD 140, Elverado CUSD 196, Giant City CCSD 130, DeSoto Cons SD 86 |
| Jasper County | 1 | 1,197 | Jasper County CUD 1 |
| Jefferson County | 14 | 5,314 | All 14 Jefferson County districts → |
| Jersey County | 1 | 2,365 | Jersey CUSD 100 |
| Jo Daviess County | 6 | 3,012 | Galena USD 120, East Dubuque USD 119, Stockton CUSD 206, River Ridge CUSD 210, Warren CUSD 205, Scales Mound CUSD 211 |
| Johnson County | 6 | 1,743 | Goreville CUD 1, Vienna SD 55, Vienna HSD 133, New Simpson Hill SD 32, Cypress SD 64, Buncombe Cons SD 43 |
| Kane County | 9 | 88,881 | SD U-46, Aurora East USD 131, St Charles CUSD 303, Aurora West USD 129, Batavia USD 101, Central CUSD 301, Geneva CUSD 304, Kaneland CUSD 302, Illinois Mathematics & Science Academy |
| Kankakee County | 11 | 16,039 | All 11 Kankakee County districts → |
| Kendall County | 6 | 26,839 | CUSD 308, Yorkville CUSD 115, Plano CUSD 88, Newark CCSD 66, Newark CHSD 18, Lisbon CCSD 90 |
| Knox County | 5 | 6,611 | Galesburg CUSD 205, Knoxville CUSD 202, Abingdon-Avon CUSD 276, R O W V A CUSD 208, Williamsfield CUSD 210 |
| Lake County | 44 | 113,693 | All 44 Lake County districts → |
| LaSalle County | 26 | 14,523 | All 26 LaSalle County districts → |
| Lawrence County | 2 | 1,964 | Lawrence County CUD 20, Red Hill CUSD 10 |
| Lee County | 5 | 3,778 | Dixon USD 170, Amboy CUSD 272, Ashton-Franklin Center CUSD 275, Paw Paw CUSD 271, Steward ESD 220 |
| Livingston County | 11 | 5,419 | All 11 Livingston County districts → |
| Logan County | 7 | 3,117 | Lincoln ESD 27, Lincoln CHSD 404, Mt Pulaski CUSD 23, Chester-East Lincoln CCSD 61, West Lincoln-Broadwell ESD 92, Hartsburg Emden CUSD 21, New Holland-Middletown ED 88 |
| Macon County | 7 | 14,962 | Decatur SD 61, Mt Zion CUSD 3, Maroa Forsyth CUSD 2, Warrensburg-Latham CUSD 11, Meridian CUSD 15, Argenta-Oreana CUSD 1, Sangamon Valley CUSD 9 |
| Macoupin County | 8 | 7,221 | Carlinville CUSD 1, Staunton CUSD 6, North Mac CUSD 34, Southwestern CUSD 9, Gillespie CUSD 7, Bunker Hill CUSD 8, Mount Olive CUSD 5, Northwestern CUSD 2 |
| Madison County | 13 | 37,688 | All 13 Madison County districts → |
| Marion County | 13 | 6,089 | All 13 Marion County districts → |
| Marshall County | 2 | 1,191 | Midland CUSD 7, Henry-Senachwine CUSD 5 |
| Mason County | 3 | 2,307 | Midwest Central CUSD 191, Havana CUSD 126, Illini Central CUSD 189 |
| Massac County | 2 | 2,026 | Massac UD 1, Joppa-Maple Grove UD 38 |
| McDonough County | 3 | 3,250 | Macomb CUSD 185, Bushnell Prairie City CUSD 170, West Prairie CUSD 103 |
| McHenry County | 19 | 65,995 | All 19 McHenry County districts → |
| McLean County | 9 | 23,756 | McLean County USD 5, Bloomington SD 87, Olympia CUSD 16, ISU Laboratory Schools, Tri Valley CUSD 3, Heyworth CUSD 4, LeRoy CUSD 2, Ridgeview CUSD 19, Lexington CUSD 7 |
| Menard County | 3 | 2,219 | Porta CUSD 202, Athens CUSD 213, Greenview CUSD 200 |
| Mercer County | 2 | 2,579 | Sherrard CUSD 200, Mercer County School District 404 |
| Monroe County | 3 | 5,006 | Waterloo CUSD 5, Columbia CUSD 4, Valmeyer CUSD 3 |
| Montgomery County | 4 | 3,835 | Hillsboro CUSD 3, Litchfield CUSD 12, Nokomis CUSD 22, Panhandle CUSD 2 |
| Morgan County | 5 | 4,446 | Jacksonville SD 117, Triopia CUSD 27, Waverly CUSD 6, Franklin CUSD 1, Meredosia-Chambersburg CUSD 11 |
| Moultrie County | 2 | 1,604 | Sullivan CUSD 300, Okaw Valley CUSD 302 |
| Ogle County | 10 | 8,339 | All 10 Ogle County districts → |
| Peoria County | 18 | 27,428 | All 18 Peoria County districts → |
| Perry County | 5 | 2,545 | Du Quoin CUSD 300, Pinckneyville SD 50, Pinckneyville CHSD 101, CCSD 204, Tamaroa School Dist 5 |
| Piatt County | 4 | 2,645 | Monticello CUSD 25, Cerro Gordo CUSD 100, Bement CUSD 5, Deland-Weldon CUSD 57 |
| Pike County | 4 | 2,394 | Pikeland CUSD 10, Western CUSD 12, Pleasant Hill CUSD 3, Griggsville-Perry CUSD 4 |
| Pope County | 1 | 442 | Pope Co CUD 1 |
| Pulaski County | 2 | 750 | Meridian CUSD 101, Century CUSD 100 |
| Putnam County | 1 | 773 | Putnam County CUSD 535 |
| Randolph County | 7 | 3,876 | Sparta CUSD 140, Red Bud CUSD 132, Chester CUSD 139, Steeleville CUSD 138, Coulterville USD 1, Prairie Du Rocher CCSD 134, Chester N HSD 122 |
| Richland County | 1 | 2,145 | Richland County CUSD 1 |
| Rock Island County | 9 | 21,283 | Moline-Coal Valley CUSD 40, Rock Island SD 41, East Moline SD 37, United Twp HSD 30, Riverdale CUSD 100, Rockridge CUSD 300, Silvis SD 34, Carbon Cliff-Barstow SD 36, Hampton SD 29 |
| Saline County | 4 | 3,662 | Harrisburg CUSD 3, Eldorado CUSD 4, Carrier Mills-Stonefort CUSD 2, Galatia CUSD 1 |
| Sangamon County | 10 | 26,567 | All 10 Sangamon County districts → |
| Schuyler County | 1 | 843 | Schuyler-Industry CUSD 5 |
| Scott County | 2 | 736 | Winchester CUSD 1, Scott-Morgan CUSD 2 |
| Shelby County | 4 | 2,383 | Shelbyville CUSD 4, Stewardson-Strasburg CUD 5A, Windsor CUSD 1, Cowden-Herrick CUSD 3A |
| St. Clair County | 27 | 38,365 | All 27 St. Clair County districts → |
| Stark County | 2 | 837 | Stark County CUSD 100, Bradford CUSD 1 |
| Stephenson County | 5 | 6,022 | Freeport SD 145, Lena Winslow CUSD 202, Dakota CUSD 201, Pearl City CUSD 200, Orangeville CUSD 203 |
| Tazewell County | 18 | 18,143 | All 18 Tazewell County districts → |
| Union County | 7 | 2,478 | Anna CCSD 37, Anna Jonesboro CHSD 81, Cobden SUD 17, County of Union Sch Dist No43, Shawnee CUSD 84, Dongola USD 66, Lick Creek CCSD 16 |
| Vermilion County | 12 | 11,267 | All 12 Vermilion County districts → |
| Wabash County | 2 | 1,513 | Wabash CUSD 348, Allendale CCSD 17 |
| Warren County | 2 | 2,587 | Monmouth-Roseville CUSD 238, United CUSD 304 |
| Washington County | 6 | 1,739 | Nashville CCSD 49, West Washington Co CUD 10, Nashville CHSD 99, Ashley CCSD 15, Irvington CCSD 11, Oakdale CCSD 1 |
| Wayne County | 7 | 2,404 | Fairfield PSD 112, Wayne City CUSD 100, Fairfield Comm H S Dist 225, North Wayne CUSD 200, New Hope CCSD 6, Jasper CCSD 17, Geff CCSD 14 |
| White County | 3 | 2,168 | Carmi-White County CUSD 5, Norris City-Omaha-Enfield CUSD 3, Grayville CUSD 1 |
| Whiteside County | 9 | 8,445 | Sterling CUSD 5, River Bend CUSD 2, Morrison CUSD 6, Rock Falls ESD 13, Prophetstown-Lyndon-Tampico CUSD3, Erie CUSD 1, Rock Falls Twp HSD 301, East Coloma - Nelson CESD 20, Montmorency CCSD 145 |
| Will County | 30 | 104,081 | All 30 Will County districts → |
| Williamson County | 5 | 9,700 | Marion CUSD 2, Herrin CUSD 4, Carterville CUSD 5, Johnston City CUSD 1, Crab Orchard CUSD 3 |
| Winnebago County | 11 | 44,103 | All 11 Winnebago County districts → |
| Woodford County | 9 | 7,068 | Eureka CUD 140, El Paso-Gridley CUSD 11, County of Woodford School, Fieldcrest CUSD 6, Metamora CCSD 1, Germantown Hills SD 69, Roanoke Benson CUSD 60, Lowpoint-Washburn CUSD 21, Riverview CCSD 2 |