22 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Fayette | 1 | 3,307 | 3,335 | -0.06% | 84 | 40 | Township |
| Fermanagh | 2 | 2,875 | 2,870 | 0.14% | 90 | 32 | Township |
| Walker | 3 | 2,813 | 2,785 | 0.46% | 98 | 29 | Township |
| Mifflin | 4 | 2,391 | 2,259 | 1.31% | 124 | 19 | Township |
| Monroe | 5 | 2,031 | 2,046 | 0.1% | 102 | 20 | Township |
| Delaware | 6 | 1,609 | 1,615 | -0.12% | 55 | 30 | Township |
| Mifflin | 7 | 1,087 | 1,092 | -0.09% | 39 | 28 | Township |
| Turbett | 8 | 967 | 978 | 0.21% | 59 | 16 | Township |
| Mifflintown | 9 | 820 | 840 | -0.49% | 5,857 | 0 | Borough |
| Mifflin | 10 | 817 | 817 | 0.25% | 53 | 15 | Township |
| Port Royal | 11 | 792 | 810 | -0.5% | 1,316 | 1 | Borough |
| Spruce Hill | 12 | 789 | 787 | 0.51% | 36 | 22 | Township |
| Beale | 13 | 788 | 771 | 0.13% | 36 | 22 | Township |
| McAlisterville | 14 | 763 | 1,188 | -1.8% | 435 | 2 | CDP |
| Thompsontown | 15 | 637 | 625 | 0.31% | 1,954 | 0 | Borough |
| Lack | 16 | 629 | 639 | 0% | 11 | 57 | Township |
| Greenwood | 17 | 542 | 532 | -0.18% | 28 | 19 | Township |
| Mifflin | 18 | 517 | 531 | -0.58% | 2,971 | 0 | Borough |
| Mexico | 19 | 497 | 509 | 0.4% | 458 | 1 | CDP |
| Richfield | 20 | 334 | 434 | -4.02% | 287 | 1 | CDP |
| East Waterford | 21 | 181 | 174 | 7.1% | 481 | 0 | CDP |
| East Salem | 22 | 130 | 132 | -2.99% | 485 | 0 | CDP |
Fayette is the largest city in Juniata County, with a population of 3,307.
East Salem is the smallest city in Juniata County, with a population of 130.
There are 22 cities in Juniata County, Pennsylvania.