11 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Atchison | 1 | 10,787 | 10,865 | -0.12% | 1,346 | 8 | City |
| Shannon | 2 | 1,148 | 1,148 | 0.53% | 22 | 52 | Township |
| Mount Pleasant | 3 | 884 | 861 | 1.03% | 19 | 48 | Township |
| Lancaster | 4 | 756 | 748 | 0.67% | 13 | 60 | Township |
| Center | 5 | 632 | 621 | 0.8% | 12 | 54 | Township |
| Grasshopper | 6 | 510 | 508 | 0.59% | 8 | 66 | Township |
| Effingham | 7 | 484 | 492 | -0.21% | 782 | 1 | City |
| Kapioma | 8 | 256 | 254 | 0.79% | 5 | 47 | Township |
| Lancaster | 9 | 244 | 244 | 0% | 1,226 | 0 | City |
| Muscotah | 10 | 155 | 157 | 0% | 465 | 0 | City |
| Huron | 11 | 74 | 74 | 0% | 1,028 | 0 | City |
Atchison is the largest city in Atchison County, with a population of 10,787.
Huron is the smallest city in Atchison County, with a population of 74.
There are 11 cities in Atchison County, Kansas.