| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Bangor | 1 | 32,513 | 31,726 | -0.02% | 949 | 34 | City |
| Orono | 2 | 12,608 | 11,176 | 1.51% | 693 | 18 | Town |
| Brewer | 3 | 9,628 | 9,670 | -0.08% | 632 | 15 | City |
| Hampden | 4 | 8,118 | 7,731 | 0.5% | 214 | 38 | Town |
| Old Town | 5 | 7,661 | 7,427 | 0.95% | 197 | 39 | City |
| Hermon | 6 | 7,037 | 6,488 | 0.79% | 196 | 36 | Town |
| Lincoln | 7 | 4,982 | 4,853 | 0.22% | 73 | 68 | Town |
| Glenburn | 8 | 4,834 | 4,644 | 0.19% | 178 | 27 | Town |
| Millinocket | 9 | 4,082 | 4,101 | -0.32% | 257 | 16 | Town |
| Orrington | 10 | 3,921 | 3,808 | 0.23% | 157 | 25 | Town |
| Dexter | 11 | 3,876 | 3,806 | 0.05% | 110 | 35 | Town |
| Holden | 12 | 3,454 | 3,281 | 0.47% | 110 | 31 | Town |
| Levant | 13 | 3,357 | 2,939 | 2.07% | 112 | 30 | Town |
| Newport | 14 | 3,210 | 3,129 | 0.56% | 109 | 30 | Town |
| Corinth | 15 | 3,198 | 2,899 | 1.88% | 79 | 40 | Town |
| Milford | 16 | 3,115 | 3,067 | -0.06% | 68 | 46 | Town |
| Carmel | 17 | 3,046 | 2,870 | 0.49% | 83 | 37 | Town |
| Corinna | 18 | 2,266 | 2,211 | 0.22% | 59 | 39 | Town |
| Eddington | 19 | 2,250 | 2,181 | -0.18% | 90 | 25 | Town |
| Veazie | 20 | 1,879 | 1,815 | 0.8% | 621 | 3 | Town |
| Newburgh | 21 | 1,747 | 1,605 | 0.69% | 56 | 31 | Town |
| Charleston | 22 | 1,658 | 1,551 | 0.85% | 41 | 41 | Town |
| Bradley | 23 | 1,587 | 1,532 | 0.38% | 32 | 50 | Town |
| East Millinocket | 24 | 1,562 | 1,570 | -0.32% | 220 | 7 | Town |
| Greenbush | 25 | 1,543 | 1,446 | 0.78% | 35 | 44 | Town |
| Hudson | 26 | 1,511 | 1,418 | 1.89% | 40 | 38 | Town |
| Enfield | 27 | 1,441 | 1,430 | -0.21% | 52 | 28 | Town |
| Kenduskeag | 28 | 1,421 | 1,341 | 0.21% | 85 | 17 | Town |
| Plymouth | 29 | 1,324 | 1,327 | -0.3% | 45 | 30 | Town |
| Stetson | 30 | 1,257 | 1,189 | 1.13% | 36 | 35 | Town |
| Bradford | 31 | 1,254 | 1,181 | 0.56% | 30 | 41 | Town |
| Etna | 32 | 1,246 | 1,227 | 0.08% | 50 | 25 | Town |
| Dixmont | 33 | 1,213 | 1,208 | -0.16% | 33 | 36 | Town |
| Medway | 34 | 1,197 | 1,187 | 0% | 29 | 41 | Town |
| Howland | 35 | 1,164 | 1,099 | -0.17% | 33 | 35 | Town |
| Garland | 36 | 1,045 | 1,019 | 0.58% | 28 | 38 | Town |
| Exeter | 37 | 1,007 | 964 | 0.5% | 26 | 39 | Town |
| Lee | 38 | 921 | 917 | -0.22% | 24 | 39 | Town |
| Patten | 39 | 900 | 882 | 0% | 24 | 38 | Town |
| Clifton | 40 | 880 | 845 | 0.57% | 25 | 35 | Town |
| Alton | 41 | 841 | 828 | -0.12% | 20 | 42 | Town |
| Lagrange | 42 | 648 | 635 | 0.15% | 13 | 49 | Town |
| Mattawamkeag | 43 | 610 | 593 | 0.49% | 16 | 38 | Town |
| Chester | 44 | 551 | 547 | -0.36% | 12 | 46 | Town |
| Burlington | 45 | 461 | 383 | 2.44% | 9.0 | 54 | Town |
| Springfield | 46 | 413 | 297 | 5.9% | 11 | 38 | Town |
| Winn | 47 | 403 | 398 | -0.49% | 9.0 | 44 | Town |
| Lowell | 48 | 390 | 367 | 0.52% | 10 | 38 | Town |
| Penobscot Indian Island Reservation | 49 | 378 | 371 | 0.27% | 50 | 8 | Township |
| Stacyville | 50 | 374 | 374 | -0.27% | 9.0 | 40 | Town |
| Passadumkeag | 51 | 348 | 346 | -0.29% | 15 | 23 | Town |
| Woodville | 52 | 203 | 203 | -0.49% | 5.0 | 43 | Town |
| Mount Chase | 53 | 189 | 189 | -0.53% | 5.0 | 37 | Town |
| Carroll | 54 | 141 | 138 | 0.71% | 3.0 | 44 | Plantation |
| Edinburg | 55 | 136 | 134 | 0% | 4.0 | 35 | Town |
| Maxfield | 56 | 107 | 81 | 8.08% | 6.0 | 19 | Town |
| Lakeville | 57 | 105 | 104 | 0% | 2.0 | 58 | Town |
| Webster | 58 | 65 | 63 | 1.56% | 2.0 | 37 | Plantation |
| Seboeis | 59 | 39 | 39 | 0% | 1.0 | 40 | Plantation |
Bangor is the largest city in Penobscot County, with a population of 32,513.
Seboeis is the smallest city in Penobscot County, with a population of 39.
There are 59 cities in Penobscot County, Maine.