26 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Gettysburg | 1 | 9,418 | 7,104 | 4.27% | 5,673 | 2 | Borough |
| Conewago | 2 | 8,205 | 7,872 | 0.74% | 788 | 10 | Township |
| Cumberland | 3 | 7,318 | 7,032 | 0.72% | 219 | 33 | Township |
| Straban | 4 | 5,035 | 4,857 | 0.64% | 147 | 34 | Township |
| Littlestown | 5 | 4,982 | 4,787 | 0.67% | 2,724 | 2 | Borough |
| Carroll Valley | 6 | 4,105 | 3,940 | 0.69% | 763 | 5 | Borough |
| Menallen | 7 | 3,874 | 3,698 | 0.83% | 91 | 43 | Township |
| McSherrystown | 8 | 3,202 | 3,079 | 0.66% | 6,254 | 1 | Borough |
| Union | 9 | 3,194 | 3,063 | 0.73% | 185 | 17 | Township |
| Germany | 10 | 2,963 | 2,842 | 0.75% | 274 | 11 | Township |
| Fairfield | 11 | 2,838 | 2,831 | 0.28% | 234 | 12 | Township |
| Latimore | 12 | 2,756 | 2,643 | 0.77% | 130 | 21 | Township |
| Huntington | 13 | 2,492 | 2,391 | 0.77% | 99 | 25 | Township |
| Hamiltonban | 14 | 2,390 | 2,297 | 0.67% | 61 | 39 | Township |
| Fairfield | 15 | 2,020 | 2,046 | -0.15% | 33 | 61 | Township |
| New Oxford | 16 | 1,947 | 1,868 | 0.67% | 3,145 | 1 | Borough |
| Bonneauville | 17 | 1,829 | 1,759 | 0.66% | 1,893 | 1 | Borough |
| East Berlin | 18 | 1,603 | 1,542 | 0.63% | 2,280 | 1 | Borough |
| Biglerville | 19 | 1,271 | 1,226 | 0.63% | 1,952 | 1 | Borough |
| Abbottstown | 20 | 1,060 | 1,020 | 0.66% | 1,941 | 1 | Borough |
| Highland | 21 | 1,038 | 999 | 0.68% | 86 | 12 | Township |
| Fairfield | 22 | 986 | 1,009 | -0.1% | 51 | 19 | Township |
| Arendtsville | 23 | 903 | 867 | 0.67% | 1,127 | 1 | Borough |
| Bendersville | 24 | 771 | 737 | 0.78% | 1,706 | 0 | Borough |
| York Springs | 25 | 713 | 682 | 0.71% | 3,583 | 0 | Borough |
| Fairfield | 26 | 552 | 528 | 0.73% | 820 | 1 | Borough |
Gettysburg is the largest city in Adams County, with a population of 9,418.
Fairfield is the smallest city in Adams County, with a population of 552.
There are 26 cities in Adams County, Pennsylvania.