8 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Atlantic | 1 | 6,774 | 6,791 | -0.04% | 817 | 8.29 | City |
| Griswold | 2 | 989 | 993 | -0.1% | 1,624 | 0.61 | City |
| Anita | 3 | 965 | 964 | 0% | 544 | 1.77 | City |
| Lewis | 4 | 364 | 359 | 0.28% | 721 | 0.51 | City |
| Massena | 5 | 354 | 356 | 0% | 517 | 0.69 | City |
| Cumberland | 6 | 251 | 248 | 0.4% | 405 | 0.62 | City |
| Marne | 7 | 112 | 109 | 0.9% | 200 | 0.56 | City |
| Wiota | 8 | 91 | 91 | 0% | 304 | 0.30 | City |
Atlantic is the largest city in Cass County, with a population of 6,774.
Wiota is the smallest city in Cass County.
There are 8 cities in Cass County, Iowa.