22 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Fayette township | 1 | 3,270 | 3,332 | -0.3% | 83 | 39.54 | Township |
| Fermanagh township | 2 | 2,854 | 2,867 | 0.04% | 89 | 32.05 | Township |
| Walker township | 3 | 2,773 | 2,789 | -0.04% | 96 | 28.83 | Township |
| Mifflin township | 4 | 2,418 | 2,272 | 1.72% | 126 | 19.24 | Township |
| Monroe township | 5 | 2,000 | 2,045 | -0.3% | 101 | 19.89 | Township |
| Delaware township | 6 | 1,597 | 1,610 | -0.06% | 54 | 29.52 | Township |
| Mifflin township | 7 | 1,076 | 1,092 | -0.28% | 39 | 27.72 | Township |
| Turbett township | 8 | 938 | 976 | -0.95% | 57 | 16.37 | Township |
| Mifflintown | 9 | 804 | 838 | -0.86% | 5,743 | 0.14 | Borough |
| Mifflin township | 10 | 803 | 817 | -0.5% | 52 | 15.50 | Township |
| Beale township | 11 | 794 | 770 | 0.89% | 36 | 21.89 | Township |
| Port Royal | 12 | 780 | 812 | -0.76% | 1,296 | 0.60 | Borough |
| Spruce Hill township | 13 | 777 | 789 | 0% | 36 | 21.75 | Township |
| McAlisterville | 14 | 763 | 1,188 | -1.8% | 435 | 1.75 | CDP |
| Thompsontown | 15 | 620 | 627 | -0.16% | 1,902 | 0.33 | Borough |
| Lack township | 16 | 617 | 635 | -0.48% | 11 | 57.03 | Township |
| Greenwood township | 17 | 552 | 537 | 0.55% | 28 | 19.46 | Township |
| Mifflin | 18 | 509 | 531 | -0.78% | 2,925 | 0.17 | Borough |
| Mexico | 19 | 497 | 509 | 0.4% | 458 | 1.08 | CDP |
| Richfield | 20 | 334 | 434 | -4.02% | 287 | 1.16 | CDP |
| East Waterford | 21 | 181 | 174 | 7.1% | 481 | 0.38 | CDP |
| East Salem | 22 | 130 | 132 | -2.99% | 485 | 0.27 | CDP |
Fayette township is the largest city in Juniata County, with a population of 3,270.
East Salem is the smallest city in Juniata County.
There are 22 cities in Juniata County, Pennsylvania.