9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| WaKeeney | 1 | 2,085 | 2,100 | 0.53% | 12 | 180 | Township |
| WaKeeney | 2 | 1,760 | 1,788 | -0.34% | 987 | 2 | City |
| Collyer | 3 | 289 | 293 | 0.35% | 1 | 200 | Township |
| Ogallah | 4 | 167 | 162 | 1.21% | 1 | 144 | Township |
| Collyer | 5 | 93 | 95 | -1.06% | 397 | 0 | City |
| Riverside | 6 | 87 | 87 | 1.16% | 1 | 115 | Township |
| Glencoe | 7 | 67 | 68 | 0% | 2 | 36 | Township |
| Wilcox | 8 | 65 | 64 | 1.56% | 1 | 115 | Township |
| Ogallah | 9 | 15 | 10 | 7.14% | 9 | 2 | CDP |
WaKeeney is the largest city in Trego County, with a population of 2,085.
Ogallah is the smallest city in Trego County, with a population of 15.
There are 9 cities in Trego County, Kansas.