25 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Gettysburg | 1 | 9,375 | 7,107 | 5.09% | 5,648 | 1.66 | Borough |
| Conewago township | 2 | 8,120 | 7,867 | 0.77% | 780 | 10.41 | Township |
| Cumberland township | 3 | 7,244 | 7,027 | 0.74% | 217 | 33.44 | Township |
| Straban township | 4 | 4,999 | 4,862 | 0.66% | 146 | 34.30 | Township |
| Littlestown | 5 | 4,918 | 4,787 | 0.53% | 2,689 | 1.83 | Borough |
| Carroll Valley | 6 | 4,048 | 3,938 | 0.55% | 753 | 5.38 | Borough |
| Menallen township | 7 | 3,830 | 3,695 | 0.84% | 90 | 42.70 | Township |
| Union township | 8 | 3,163 | 3,063 | 0.77% | 183 | 17.29 | Township |
| McSherrystown | 9 | 3,160 | 3,079 | 0.51% | 6,172 | 0.51 | Borough |
| Germany township | 10 | 2,929 | 2,843 | 0.69% | 271 | 10.82 | Township |
| Fairfield township | 11 | 2,777 | 2,831 | -0.4% | 229 | 12.14 | Township |
| Latimore township | 12 | 2,725 | 2,643 | 0.74% | 129 | 21.15 | Township |
| Huntington township | 13 | 2,471 | 2,392 | 0.82% | 99 | 25.05 | Township |
| Hamiltonban township | 14 | 2,369 | 2,295 | 0.77% | 61 | 39.14 | Township |
| Fairfield township | 15 | 2,020 | 2,047 | -0.25% | 33 | 61.36 | Township |
| New Oxford | 16 | 1,923 | 1,867 | 0.57% | 3,107 | 0.62 | Borough |
| Bonneauville | 17 | 1,806 | 1,760 | 0.5% | 1,870 | 0.97 | Borough |
| East Berlin | 18 | 1,583 | 1,543 | 0.51% | 2,252 | 0.70 | Borough |
| Biglerville | 19 | 1,257 | 1,227 | 0.48% | 1,931 | 0.65 | Borough |
| Abbottstown | 20 | 1,053 | 1,023 | 0.57% | 1,929 | 0.55 | Borough |
| Highland township | 21 | 1,027 | 0 | 0.69% | 85 | 12.14 | Township |
| Arendtsville | 22 | 890 | 867 | 0.56% | 1,111 | 0.80 | Borough |
| Bendersville | 23 | 756 | 736 | 0.53% | 1,673 | 0.45 | Borough |
| York Springs | 24 | 706 | 685 | 0.57% | 3,548 | 0.20 | Borough |
| Fairfield | 25 | 546 | 530 | 0.55% | 811 | 0.67 | Borough |
Gettysburg is the largest city in Adams County, with a population of 9,375.
Fairfield is the smallest city in Adams County.
There are 25 cities in Adams County, Pennsylvania.