2 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Petersburg | 1 | 4,146 | 3,170 | 7.13% | 94 | 44 | CDP |
| Kupreanof | 2 | 19 | 19 | 0% | 6 | 3 | City |
Petersburg is the largest city in Petersburg Borough, with a population of 4,146.
Kupreanof is the smallest city in Petersburg Borough, with a population of 19.
There are 2 cities in Petersburg Borough, Alaska.