11 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Junction City | 1 | 21,128 | 22,947 | -1.69% | 1,830 | 11.54 | City |
| Fort Riley | 2 | 8,839 | 8,720 | 0.82% | 1,379 | 6.41 | CDP |
| Smoky Hill township | 3 | 8,562 | 9,218 | -1.36% | 158 | 54.05 | Township |
| Jefferson township | 4 | 1,996 | 2,141 | -1.29% | 42 | 47.17 | Township |
| Milford township | 5 | 1,519 | 1,631 | -1.36% | 38 | 39.62 | Township |
| Milford | 6 | 376 | 405 | -1.57% | 657 | 0.57 | City |
| Lyon township | 7 | 262 | 281 | -1.13% | 6 | 43.25 | Township |
| Wingfield township | 8 | 170 | 185 | -1.73% | 4 | 47.36 | Township |
| Blakely township | 9 | 97 | 104 | -1.02% | 3 | 35.67 | Township |
| Jackson township | 10 | 66 | 71 | -1.49% | 2 | 40.28 | Township |
| Zeandale | 11 | 34 | 62 | 6.25% | 25 | 1.36 | CDP |
Junction City is the largest city in Geary County, with a population of 21,128.
Zeandale is the smallest city in Geary County.
There are 11 cities in Geary County, Kansas.