34 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Hamilton | 1 | 11,772 | 11,384 | 0.74% | 331 | 36 | Township |
| Hamilton | 2 | 8,480 | 8,591 | -0.02% | 221 | 38 | Township |
| Punxsutawney | 3 | 5,495 | 5,771 | -0.83% | 1,633 | 3 | Borough |
| Brookville | 4 | 3,852 | 3,993 | -0.59% | 1,224 | 3 | Borough |
| Hamilton | 5 | 2,827 | 2,711 | 0.75% | 209 | 13 | Township |
| Winslow | 6 | 2,451 | 2,547 | -0.65% | 54 | 45 | Township |
| Reynoldsville | 7 | 2,450 | 2,546 | -0.65% | 1,765 | 1 | Borough |
| Snyder | 8 | 2,278 | 2,366 | -0.65% | 55 | 41 | Township |
| Brockway | 9 | 2,199 | 2,279 | -0.59% | 1,856 | 1 | Borough |
| Coolspring | 10 | 2,056 | 2,109 | -0.39% | 110 | 19 | Township |
| Bell | 11 | 1,943 | 2,009 | -0.51% | 105 | 19 | Township |
| Henderson | 12 | 1,874 | 1,940 | -0.58% | 85 | 22 | Township |
| Young | 13 | 1,643 | 1,712 | -0.73% | 106 | 15 | Township |
| Warsaw | 14 | 1,312 | 1,366 | -0.68% | 26 | 51 | Township |
| Pine Creek | 15 | 1,290 | 1,325 | -0.46% | 46 | 28 | Township |
| Perry | 16 | 1,203 | 1,249 | -0.58% | 42 | 28 | Township |
| Rose | 17 | 1,108 | 1,153 | -0.72% | 58 | 19 | Township |
| McCalmont | 18 | 1,094 | 1,134 | -0.55% | 42 | 26 | Township |
| Sykesville | 19 | 1,067 | 1,111 | -0.65% | 674 | 2 | Borough |
| Falls Creek | 20 | 993 | 1,031 | -0.6% | 1,065 | 1 | Borough |
| Union | 21 | 821 | 849 | -0.48% | 47 | 18 | Township |
| Ringgold | 22 | 748 | 771 | -0.4% | 39 | 19 | Township |
| Gaskill | 23 | 651 | 675 | -0.61% | 30 | 21 | Township |
| Big Run | 24 | 614 | 637 | -0.65% | 889 | 1 | Borough |
| Hamilton | 25 | 528 | 555 | -0.38% | 7 | 72 | Township |
| Hamilton | 26 | 527 | 534 | -0.19% | 49 | 11 | Township |
| Summerville | 27 | 494 | 511 | -0.6% | 830 | 1 | Borough |
| Clover | 28 | 414 | 429 | -0.72% | 26 | 16 | Township |
| Corsica | 29 | 311 | 320 | -0.32% | 687 | 0 | Borough |
| Porter | 30 | 288 | 299 | -0.69% | 16 | 18 | Township |
| Barnett | 31 | 221 | 231 | -0.9% | 15 | 15 | Township |
| Timblin | 32 | 142 | 145 | 0% | 157 | 1 | Borough |
| Heath | 33 | 112 | 117 | -0.88% | 4 | 28 | Township |
| Worthville | 34 | 70 | 73 | 0% | 391 | 0 | Borough |
Hamilton is the largest city in Jefferson County, with a population of 11,772.
Worthville is the smallest city in Jefferson County, with a population of 70.
There are 34 cities in Jefferson County, Pennsylvania.