| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Mableton | 1 | 79,174 | 77,112 | 83.2% | 2,182 | 36 | City |
| Mableton | 2 | 79,174 | 77,112 | 0.45% | 2,182 | 36 | City |
| Marietta | 3 | 64,152 | 61,046 | 0.91% | 2,698 | 24 | City |
| Smyrna | 4 | 57,798 | 56,147 | 0.5% | 3,572 | 16 | City |
| Mableton | 5 | 43,623 | 77,112 | 0.94% | 1,202 | 36 | City |
| Mableton | 6 | 43,623 | 77,112 | -44.65% | 1,202 | 36 | City |
| Kennesaw | 7 | 39,061 | 33,363 | 2.87% | 4,003 | 10 | City |
| Powder Springs | 8 | 21,688 | 16,915 | 3.26% | 2,702 | 8 | City |
| Austell | 9 | 8,443 | 7,855 | 1.25% | 1,331 | 6 | City |
Mableton is the largest city in Cobb County, with a population of 79,174.
Austell is the smallest city in Cobb County, with a population of 8,443.
There are 9 cities in Cobb County, Georgia.