25 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Mableton | 1 | 78,614 | 41,647 | 85.4% | 3,850 | 20 | CDP |
| Mableton | 2 | 78,614 | 77,080 | 85.4% | 3,850 | 20 | CDP |
| Mableton | 3 | 78,614 | 77,114 | 85.4% | 3,850 | 20 | CDP |
| Mableton | 4 | 78,614 | 41,647 | 0.38% | 3,850 | 20 | CDP |
| Mableton | 5 | 78,614 | 77,080 | 0.38% | 3,850 | 20 | CDP |
| Mableton | 6 | 78,614 | 77,114 | 0.38% | 3,850 | 20 | CDP |
| Marietta | 7 | 63,643 | 61,055 | 0.83% | 2,707 | 24 | City |
| Marietta | 8 | 63,643 | 61,036 | 0.83% | 2,707 | 24 | City |
| Smyrna | 9 | 57,429 | 56,199 | 0.44% | 3,591 | 16 | City |
| Smyrna | 10 | 57,429 | 56,167 | 0.44% | 3,591 | 16 | City |
| Mableton | 11 | 42,780 | 41,647 | 0.89% | 2,095 | 20 | CDP |
| Mableton | 12 | 42,780 | 77,080 | 0.89% | 2,095 | 20 | CDP |
| Mableton | 13 | 42,780 | 77,114 | 0.89% | 2,095 | 20 | CDP |
| Mableton | 14 | 42,780 | 41,647 | -45.37% | 2,095 | 20 | CDP |
| Mableton | 15 | 42,780 | 77,080 | -45.37% | 2,095 | 20 | CDP |
| Mableton | 16 | 42,780 | 77,114 | -45.37% | 2,095 | 20 | CDP |
| Kennesaw | 17 | 38,832 | 33,236 | 2.89% | 3,980 | 10 | City |
| Kennesaw | 18 | 38,832 | 33,371 | 2.89% | 3,980 | 10 | City |
| Powder Springs | 19 | 20,311 | 16,910 | 3.46% | 2,601 | 8 | City |
| Powder Springs | 20 | 20,311 | 16,914 | 3.46% | 2,601 | 8 | City |
| Vinings | 21 | 13,750 | 12,546 | 1.99% | 4,399 | 3 | CDP |
| Fair Oaks | 22 | 9,961 | 9,447 | 1.17% | 5,103 | 2 | CDP |
| Austell | 23 | 8,345 | 7,835 | 1.23% | 1,316 | 6 | City |
| Austell | 24 | 8,345 | 7,840 | 1.23% | 1,316 | 6 | City |
| Kennesaw State University | 25 | 3,302 | 3,568 | 7.14% | 8,423 | 0 | CDP |
Mableton is the largest city in Cobb County, with a population of 78,614.
Kennesaw State University is the smallest city in Cobb County, with a population of 3,302.
There are 25 cities in Cobb County, Georgia.