9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Mableton | 1 | 78,614 | 77,114 | 83.63% | 2,166 | 36 | City |
| Mableton | 2 | 78,614 | 77,114 | 0.38% | 2,166 | 36 | City |
| Marietta | 3 | 63,643 | 61,036 | 0.83% | 2,676 | 24 | City |
| Smyrna | 4 | 57,429 | 56,167 | 0.44% | 3,549 | 16 | City |
| Mableton | 5 | 43,217 | 77,114 | 0.95% | 1,191 | 36 | City |
| Mableton | 6 | 43,217 | 77,114 | -44.82% | 1,191 | 36 | City |
| Kennesaw | 7 | 38,832 | 33,371 | 2.89% | 3,980 | 10 | City |
| Powder Springs | 8 | 20,311 | 16,914 | 3.46% | 2,531 | 8 | City |
| Austell | 9 | 8,345 | 7,840 | 1.23% | 1,316 | 6 | City |
Mableton is the largest city in Cobb County, with a population of 78,614.
Austell is the smallest city in Cobb County, with a population of 8,345.
There are 9 cities in Cobb County, Georgia.