| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Gettysburg | 1 | 8,674 | 7,106 | 3.69% | 5,225 | 2 | Borough |
| Conewago | 2 | 8,110 | 7,871 | 0.43% | 779 | 10 | Township |
| Cumberland | 3 | 7,250 | 7,032 | 0.43% | 217 | 33 | Township |
| Straban | 4 | 4,987 | 4,853 | 0.38% | 145 | 34 | Township |
| Littlestown | 5 | 4,920 | 4,776 | 0.51% | 2,690 | 2 | Borough |
| Carroll Valley | 6 | 4,072 | 3,945 | 0.52% | 757 | 5 | Borough |
| Menallen | 7 | 3,818 | 3,702 | 0.42% | 89 | 43 | Township |
| Union | 8 | 3,177 | 3,083 | 0.41% | 184 | 17 | Township |
| McSherrystown | 9 | 3,165 | 3,075 | 0.48% | 6,182 | 1 | Borough |
| Germany | 10 | 2,925 | 2,838 | 0.41% | 270 | 11 | Township |
| Fairfield | 11 | 2,804 | 2,824 | -0.07% | 231 | 12 | Township |
| Latimore | 12 | 2,727 | 2,644 | 0.44% | 129 | 21 | Township |
| Huntington | 13 | 2,449 | 2,375 | 0.45% | 98 | 25 | Township |
| Hamiltonban | 14 | 2,358 | 2,289 | 0.47% | 60 | 39 | Township |
| Fairfield | 15 | 2,028 | 2,055 | -0.29% | 33 | 61 | Township |
| New Oxford | 16 | 1,921 | 1,864 | 0.47% | 3,103 | 1 | Borough |
| Bonneauville | 17 | 1,811 | 1,758 | 0.5% | 1,875 | 1 | Borough |
| East Berlin | 18 | 1,590 | 1,545 | 0.51% | 2,262 | 1 | Borough |
| Biglerville | 19 | 1,245 | 1,213 | 0.4% | 1,912 | 1 | Borough |
| Abbottstown | 20 | 1,054 | 1,021 | 0.57% | 1,930 | 1 | Borough |
| Highland | 21 | 1,024 | 994 | 0.39% | 84 | 12 | Township |
| Fairfield | 22 | 976 | 1,006 | -0.41% | 50 | 19 | Township |
| Arendtsville | 23 | 894 | 867 | 0.45% | 1,116 | 1 | Borough |
| Bendersville | 24 | 761 | 738 | 0.53% | 1,684 | 0 | Borough |
| York Springs | 25 | 703 | 679 | 0.57% | 3,533 | 0 | Borough |
| Fairfield | 26 | 544 | 529 | 0.37% | 808 | 1 | Borough |
Gettysburg is the largest city in Adams County, with a population of 8,674.
Fairfield is the smallest city in Adams County, with a population of 544.
There are 26 cities in Adams County, Pennsylvania.