6 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Beardstown | 1 | 5,629 | 5,928 | -1.05% | 1,555 | 3.62 | City |
| Virginia | 2 | 1,422 | 1,512 | -1.25% | 1,178 | 1.21 | City |
| Ashland | 3 | 1,151 | 1,216 | -1.12% | 1,539 | 0.75 | Village |
| Lake Petersburg | 4 | 774 | 547 | 0.52% | 428 | 1.81 | CDP |
| Chandlerville | 5 | 501 | 531 | -1.18% | 631 | 0.79 | Village |
| Arenzville | 6 | 342 | 364 | -1.16% | 445 | 0.77 | Village |
Beardstown is the largest city in Cass County, with a population of 5,629.
Arenzville is the smallest city in Cass County.
There are 6 cities in Cass County, Illinois.