48 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Coal township | 1 | 10,303 | 10,123 | 2.82% | 392 | 26.30 | Township |
| Sunbury | 2 | 9,429 | 9,704 | -0.58% | 4,698 | 2.01 | City |
| Shamokin | 3 | 6,718 | 6,930 | -0.62% | 8,143 | 0.82 | City |
| Milton | 4 | 6,418 | 6,615 | -0.6% | 1,850 | 3.47 | Borough |
| Mount Carmel | 5 | 5,573 | 5,727 | -0.55% | 8,418 | 0.66 | Borough |
| Delaware township | 6 | 4,269 | 4,298 | -0.02% | 142 | 30.10 | Township |
| Ralpho township | 7 | 4,185 | 4,186 | 0.12% | 227 | 18.46 | Township |
| Northumberland | 8 | 3,794 | 3,906 | -0.58% | 2,357 | 1.61 | Borough |
| Point township | 9 | 3,764 | 3,831 | -0.37% | 150 | 25.05 | Township |
| Kulpmont | 10 | 2,667 | 2,757 | -0.67% | 2,781 | 0.96 | Borough |
| West Chillisquaque township | 11 | 2,657 | 2,602 | 0.64% | 206 | 12.88 | Township |
| Elysburg | 12 | 2,515 | 2,147 | 0.84% | 862 | 2.92 | CDP |
| Mount Carmel township | 13 | 2,432 | 2,489 | -0.37% | 112 | 21.62 | Township |
| Upper Augusta township | 14 | 2,406 | 2,472 | -0.54% | 120 | 20.02 | Township |
| Shamokin township | 15 | 2,393 | 2,372 | 0.21% | 78 | 30.81 | Township |
| Rockefeller township | 16 | 2,291 | 2,359 | -0.61% | 111 | 20.62 | Township |
| Watsontown | 17 | 2,199 | 2,236 | -0.32% | 3,102 | 0.71 | Borough |
| Edgewood | 18 | 2,185 | 2,616 | -0.59% | 4,353 | 0.50 | CDP |
| Riverside | 19 | 1,995 | 2,040 | -0.45% | 404 | 4.94 | Borough |
| Lewis township | 20 | 1,912 | 1,938 | -0.36% | 72 | 26.43 | Township |
| Turbot township | 21 | 1,795 | 1,799 | 0.17% | 130 | 13.81 | Township |
| Fairview-Ferndale | 22 | 1,761 | 2,047 | -1.45% | 1,910 | 0.92 | CDP |
| Zerbe township | 23 | 1,753 | 1,802 | -0.51% | 159 | 11.05 | Township |
| Trevorton | 24 | 1,660 | 1,624 | -0.72% | 389 | 4.26 | CDP |
| Lower Mahanoy township | 25 | 1,594 | 1,627 | -0.38% | 73 | 21.96 | Township |
| Dewart | 26 | 1,238 | 1,298 | -1.28% | 608 | 2.04 | CDP |
| Marshallton | 27 | 1,175 | 1,151 | -1.43% | 1,355 | 0.87 | CDP |
| Rush township | 28 | 1,156 | 1,194 | -0.69% | 43 | 26.64 | Township |
| Lower Augusta township | 29 | 1,014 | 1,042 | -0.59% | 56 | 18.27 | Township |
| Montandon | 30 | 839 | 892 | -0.59% | 958 | 0.88 | CDP |
| Jordan township | 31 | 759 | 783 | -0.52% | 44 | 17.18 | Township |
| Kapp Heights | 32 | 741 | 697 | -1.07% | 2,129 | 0.35 | CDP |
| Turbotville | 33 | 655 | 677 | -0.61% | 1,452 | 0.45 | Borough |
| East Chillisquaque township | 34 | 645 | 671 | -0.92% | 80 | 8.03 | Township |
| Atlas | 35 | 628 | 842 | -1.88% | 2,335 | 0.27 | CDP |
| Upper Mahanoy township | 36 | 626 | 649 | -0.95% | 27 | 23.30 | Township |
| East Cameron township | 37 | 606 | 622 | -0.49% | 52 | 11.71 | Township |
| Snydertown | 38 | 580 | 459 | 7.21% | 185 | 3.14 | CDP |
| Marion Heights | 39 | 546 | 558 | -0.36% | 3,569 | 0.15 | Borough |
| West Cameron township | 40 | 487 | 495 | 0% | 41 | 11.85 | Township |
| Little Mahanoy township | 41 | 425 | 426 | -0.47% | 39 | 10.89 | Township |
| Dalmatia | 42 | 344 | 404 | -2.82% | 504 | 0.68 | CDP |
| Herndon | 43 | 340 | 350 | -0.58% | 430 | 0.79 | Borough |
| Snydertown | 44 | 318 | 328 | -0.63% | 93 | 3.43 | Borough |
| McEwensville | 45 | 288 | 290 | 0% | 2,462 | 0.12 | Borough |
| Ranshaw | 46 | 282 | 176 | -5.37% | 2,043 | 0.14 | CDP |
| Riverside | 47 | 238 | 223 | -4.03% | 2,052 | 0.12 | CDP |
| Tharptown (Uniontown) | 48 | 212 | 370 | -8.23% | 2,163 | 0.10 | CDP |
Coal township is the largest city in Northumberland County, with a population of 10,303.
Tharptown (Uniontown) is the smallest city in Northumberland County.
There are 48 cities in Northumberland County, Pennsylvania.