17 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Fayette | 1 | 3,305 | 3,335 | -0.06% | 84 | 40 | Township |
| Fermanagh | 2 | 2,879 | 2,870 | 0.14% | 90 | 32 | Township |
| Walker | 3 | 2,826 | 2,785 | 0.46% | 98 | 29 | Township |
| Mifflin | 4 | 2,422 | 2,259 | 1.3% | 126 | 19 | Township |
| Monroe | 5 | 2,033 | 2,046 | 0.1% | 102 | 20 | Township |
| Delaware | 6 | 1,607 | 1,615 | -0.12% | 54 | 30 | Township |
| Mifflin | 7 | 1,086 | 1,092 | -0.09% | 39 | 28 | Township |
| Turbett | 8 | 969 | 978 | 0.21% | 59 | 16 | Township |
| Mifflin | 9 | 819 | 817 | 0.24% | 53 | 15 | Township |
| Mifflintown | 10 | 816 | 840 | -0.49% | 5,829 | 0 | Borough |
| Spruce Hill | 11 | 793 | 787 | 0.51% | 36 | 22 | Township |
| Beale | 12 | 789 | 771 | 0.13% | 36 | 22 | Township |
| Port Royal | 13 | 789 | 810 | -0.38% | 1,311 | 1 | Borough |
| Thompsontown | 14 | 640 | 625 | 0.47% | 1,963 | 0 | Borough |
| Lack | 15 | 629 | 639 | 0% | 11 | 57 | Township |
| Greenwood | 16 | 541 | 532 | -0.18% | 28 | 19 | Township |
| Mifflin | 17 | 514 | 531 | -0.58% | 2,954 | 0 | Borough |
Fayette is the largest city in Juniata County, with a population of 3,305.
Mifflin is the smallest city in Juniata County, with a population of 514.
There are 17 cities in Juniata County, Pennsylvania.