26 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Gettysburg | 1 | 9,032 | 7,104 | 4.45% | 5,441 | 2 | Borough |
| Conewago | 2 | 8,145 | 7,872 | 0.74% | 782 | 10 | Township |
| Cumberland | 3 | 7,266 | 7,032 | 0.72% | 217 | 33 | Township |
| Straban | 4 | 5,003 | 4,857 | 0.64% | 146 | 34 | Township |
| Littlestown | 5 | 4,949 | 4,787 | 0.65% | 2,706 | 2 | Borough |
| Carroll Valley | 6 | 4,077 | 3,940 | 0.67% | 758 | 5 | Borough |
| Menallen | 7 | 3,842 | 3,698 | 0.84% | 90 | 43 | Township |
| McSherrystown | 8 | 3,181 | 3,079 | 0.63% | 6,213 | 1 | Borough |
| Union | 9 | 3,171 | 3,063 | 0.73% | 183 | 17 | Township |
| Germany | 10 | 2,941 | 2,842 | 0.75% | 272 | 11 | Township |
| Fairfield | 11 | 2,830 | 2,831 | 0.28% | 233 | 12 | Township |
| Latimore | 12 | 2,735 | 2,643 | 0.77% | 129 | 21 | Township |
| Huntington | 13 | 2,473 | 2,391 | 0.77% | 99 | 25 | Township |
| Hamiltonban | 14 | 2,374 | 2,297 | 0.68% | 61 | 39 | Township |
| Fairfield | 15 | 2,023 | 2,046 | -0.15% | 33 | 61 | Township |
| New Oxford | 16 | 1,934 | 1,868 | 0.68% | 3,124 | 1 | Borough |
| Bonneauville | 17 | 1,817 | 1,759 | 0.61% | 1,881 | 1 | Borough |
| East Berlin | 18 | 1,593 | 1,542 | 0.63% | 2,266 | 1 | Borough |
| Biglerville | 19 | 1,263 | 1,226 | 0.56% | 1,940 | 1 | Borough |
| Abbottstown | 20 | 1,053 | 1,020 | 0.57% | 1,929 | 1 | Borough |
| Highland | 21 | 1,031 | 999 | 0.68% | 85 | 12 | Township |
| Fairfield | 22 | 987 | 1,009 | -0.1% | 51 | 19 | Township |
| Arendtsville | 23 | 897 | 867 | 0.67% | 1,120 | 1 | Borough |
| Bendersville | 24 | 765 | 737 | 0.66% | 1,692 | 0 | Borough |
| York Springs | 25 | 708 | 682 | 0.71% | 3,558 | 0 | Borough |
| Fairfield | 26 | 548 | 528 | 0.74% | 814 | 1 | Borough |
Gettysburg is the largest city in Adams County, with a population of 9,032.
Fairfield is the smallest city in Adams County, with a population of 548.
There are 26 cities in Adams County, Pennsylvania.