| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Hampden | 1 | 35,470 | 33,023 | 0.19% | 2,055 | 17 | Township |
| Upper Allen | 2 | 24,964 | 23,357 | 1.07% | 1,885 | 13 | Township |
| Carlisle | 3 | 23,309 | 20,161 | 2.71% | 4,213 | 6 | Borough |
| East Pennsboro | 4 | 21,928 | 20,910 | 1.25% | 2,080 | 11 | Township |
| Lower Allen | 5 | 21,732 | 20,113 | 2.25% | 2,160 | 10 | Township |
| South Middleton | 6 | 18,090 | 16,171 | 1.67% | 371 | 49 | Township |
| North Middleton | 7 | 13,202 | 12,140 | 1.31% | 569 | 23 | Township |
| Mechanicsburg | 8 | 10,205 | 9,284 | 1.67% | 4,233 | 2 | Borough |
| Camp Hill | 9 | 8,216 | 8,119 | 0.21% | 3,866 | 2 | Borough |
| Middlesex | 10 | 7,885 | 6,987 | 3.26% | 307 | 26 | Township |
| New Cumberland | 11 | 7,606 | 7,533 | 0.21% | 4,541 | 2 | Borough |
| Monroe | 12 | 6,778 | 6,251 | 0.44% | 260 | 26 | Township |
| Plainfield | 13 | 6,340 | 6,268 | 0.4% | 256 | 25 | Township |
| West Pennsboro | 14 | 5,707 | 5,590 | 0.14% | 189 | 30 | Township |
| Shippensburg | 15 | 5,648 | 5,479 | 0.59% | 2,785 | 2 | Borough |
| Dickinson | 16 | 5,563 | 5,308 | 0.8% | 121 | 46 | Township |
| Lemoyne | 17 | 4,833 | 4,679 | 0.67% | 2,998 | 2 | Borough |
| Shippensburg | 18 | 4,342 | 4,313 | -0.02% | 1,750 | 2 | Township |
| Wormleysburg | 19 | 3,084 | 3,053 | 0.19% | 3,969 | 1 | Borough |
| North Newton | 20 | 2,608 | 2,550 | 0.31% | 115 | 23 | Township |
| Upper Frankford | 21 | 2,356 | 2,133 | 2.04% | 121 | 19 | Township |
| Mount Holly Springs | 22 | 2,025 | 1,995 | 0.3% | 1,490 | 1 | Borough |
| Lower Frankford | 23 | 1,837 | 1,750 | 0.22% | 125 | 15 | Township |
| Lower Mifflin | 24 | 1,796 | 1,757 | 0.06% | 76 | 24 | Township |
| Shiremanstown | 25 | 1,660 | 1,646 | 0.18% | 5,425 | 0 | Borough |
| Newville | 26 | 1,413 | 1,393 | 0.28% | 3,372 | 0 | Borough |
| South Newton | 27 | 1,393 | 1,372 | 0% | 123 | 11 | Township |
| Upper Mifflin | 28 | 1,392 | 1,326 | 0.8% | 64 | 22 | Township |
| Newburg | 29 | 360 | 353 | 0.28% | 1,946 | 0 | Borough |
| Cooke | 30 | 214 | 208 | 0.47% | 11 | 20 | Township |
| Newburg | 31 | 77 | 79 | -1.28% | 42 | 2 | Borough |
Hampden is the largest city in Cumberland County, with a population of 35,470.
Newburg is the smallest city in Cumberland County, with a population of 77.
There are 31 cities in Cumberland County, Pennsylvania.