| Cities | Population |
| Alton | 25,676 |
| Collinsville | 24,707 |
| Edwardsville | 26,808 |
| Fairmont City | 2,635 |
| Granite City | 27,549 |
| Highland | 9,991 |
| Madison | 3,891 |
| Troy | 10,960 |
| Venice | 1,890 |
| Alhambra | 681 |
| District 1 | Judy Kuhn |
| District 2 | Stacey Pace |
| District 3 | Bill Meyer |
| District 4 | Bobby Ross |
| District 5 | Michael (Mick) Madison |
| District 6 | Valerie Doucleff |
| District 7 | Michael J. Walters |
| District 8 | Michael "Doc" Holliday, Sr. |
| District 9 | Bill Stoutenborough |
| District 10 | Bruce Malone |
| Chair | Karen Allen |
| School Board Member | Nita Collier |
| School Board Member | Damon Myers |
| School Board Member | Charles (Charlie) Sheads |
| School Board Member | Christopher Wingate |
Like much of southern Illinois, Madison County was a predominantly Democratic area for much of its history, but in recent elections has been moving towards the Republicans. Mitt Romney narrowly carried the county in the 2012 presidential election, becoming the first Republican presidential nominee to do so since 1984. In 2016, Donald Trump carried the largest share of the vote for any Republican presidential candidate since 1972. The county also supported the Republican candidates for governor in 2010, 2014, and 2018.
