| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Hamilton | 1 | 11,873 | 11,385 | 0.97% | 334 | 36 | Township |
| Hamilton | 2 | 8,536 | 8,594 | 0.19% | 223 | 38 | Township |
| Punxsutawney | 3 | 5,509 | 5,768 | -0.88% | 1,637 | 3 | Borough |
| Brookville | 4 | 3,856 | 3,996 | -0.7% | 1,226 | 3 | Borough |
| Hamilton | 5 | 2,791 | 2,708 | 0.47% | 207 | 13 | Township |
| Winslow | 6 | 2,485 | 2,549 | -0.08% | 55 | 45 | Township |
| Reynoldsville | 7 | 2,456 | 2,546 | -0.69% | 1,769 | 1 | Borough |
| Snyder | 8 | 2,300 | 2,366 | -0.17% | 56 | 41 | Township |
| Brockway | 9 | 2,197 | 2,279 | -0.72% | 1,854 | 1 | Borough |
| Coolspring | 10 | 2,069 | 2,114 | -0.34% | 110 | 19 | Township |
| Bell | 11 | 1,950 | 2,009 | -0.31% | 105 | 19 | Township |
| Henderson | 12 | 1,886 | 1,940 | -0.16% | 86 | 22 | Township |
| Young | 13 | 1,667 | 1,713 | -0.18% | 108 | 15 | Township |
| Warsaw | 14 | 1,331 | 1,366 | -0.15% | 26 | 51 | Township |
| Pine Creek | 15 | 1,298 | 1,326 | -0.15% | 46 | 28 | Township |
| Perry | 16 | 1,215 | 1,249 | -0.16% | 43 | 28 | Township |
| Rose | 17 | 1,114 | 1,151 | -0.36% | 58 | 19 | Township |
| McCalmont | 18 | 1,099 | 1,135 | -0.36% | 42 | 26 | Township |
| Sykesville | 19 | 1,070 | 1,111 | -0.74% | 676 | 2 | Borough |
| Falls Creek | 20 | 995 | 1,031 | -0.7% | 1,068 | 1 | Borough |
| Union | 21 | 830 | 849 | 0% | 47 | 18 | Township |
| Ringgold | 22 | 752 | 773 | -0.13% | 39 | 19 | Township |
| Gaskill | 23 | 659 | 677 | -0.15% | 31 | 21 | Township |
| Big Run | 24 | 618 | 639 | -0.64% | 894 | 1 | Borough |
| Hamilton | 25 | 526 | 538 | -0.38% | 49 | 11 | Township |
| Hamilton | 26 | 520 | 550 | -0.76% | 7.0 | 72 | Township |
| Summerville | 27 | 492 | 511 | -0.81% | 827 | 1 | Borough |
| Clover | 28 | 416 | 430 | -0.24% | 26 | 16 | Township |
| Corsica | 29 | 310 | 319 | -0.64% | 684 | 0 | Borough |
| Porter | 30 | 295 | 299 | 0.68% | 17 | 18 | Township |
| Barnett | 31 | 226 | 232 | 0% | 15 | 15 | Township |
| Timblin | 32 | 138 | 145 | -1.43% | 153 | 1 | Borough |
| Heath | 33 | 115 | 117 | 0% | 4.0 | 28 | Township |
| Worthville | 34 | 71 | 74 | -1.39% | 397 | 0 | Borough |
Hamilton is the largest city in Jefferson County, with a population of 11,873.
Worthville is the smallest city in Jefferson County, with a population of 71.
There are 34 cities in Jefferson County, Pennsylvania.