9 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Mableton | 1 | 78,914 | 77,114 | 82.6% | 2,174 | 36 | City |
| Mableton | 2 | 78,914 | 77,114 | 0.38% | 2,174 | 36 | City |
| Marietta | 3 | 64,165 | 61,036 | 0.82% | 2,698 | 24 | City |
| Smyrna | 4 | 57,682 | 56,167 | 0.44% | 3,565 | 16 | City |
| Mableton | 5 | 43,623 | 77,114 | 0.94% | 1,202 | 36 | City |
| Mableton | 6 | 43,623 | 77,114 | -44.51% | 1,202 | 36 | City |
| Kennesaw | 7 | 39,924 | 33,371 | 2.81% | 4,091 | 10 | City |
| Powder Springs | 8 | 20,991 | 16,914 | 3.35% | 2,615 | 8 | City |
| Austell | 9 | 8,446 | 7,840 | 1.21% | 1,332 | 6 | City |
Mableton is the largest city in Cobb County, with a population of 78,914.
Austell is the smallest city in Cobb County, with a population of 8,446.
There are 9 cities in Cobb County, Georgia.