12 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Lewistown | 1 | 8,319 | 8,566 | -0.59% | 4,098 | 2.03 | Borough |
| Granville township | 2 | 4,553 | 4,624 | -0.29% | 113 | 40.23 | Township |
| Brown township | 3 | 4,149 | 4,121 | 0.07% | 126 | 32.82 | Township |
| Union township | 4 | 3,661 | 3,659 | -0.24% | 144 | 25.46 | Township |
| Decatur township | 5 | 2,909 | 2,966 | -0.41% | 65 | 45.08 | Township |
| Menno township | 6 | 2,028 | 1,973 | 0.95% | 86 | 23.69 | Township |
| Burnham | 7 | 1,949 | 1,989 | -0.41% | 1,853 | 1.05 | Borough |
| Bratton township | 8 | 1,166 | 1,191 | -0.51% | 36 | 32.79 | Township |
| McClure | 9 | 881 | 890 | -0.23% | 235 | 3.75 | Borough |
| Juniata Terrace | 10 | 546 | 563 | -0.55% | 3,250 | 0.17 | Borough |
| McVeytown | 11 | 335 | 342 | -0.3% | 3,526 | 0.10 | Borough |
| Newton Hamilton | 12 | 194 | 196 | 0% | 1,252 | 0.15 | Borough |
Lewistown is the largest city in Mifflin County, with a population of 8,319.
Newton Hamilton is the smallest city in Mifflin County.
There are 12 cities in Mifflin County, Pennsylvania.