9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| WaKeeney township | 1 | 2,022 | 2,099 | -0.54% | 11 | 179.66 | Township |
| WaKeeney | 2 | 1,714 | 1,791 | -0.87% | 961 | 1.78 | City |
| Collyer township | 3 | 279 | 294 | -1.06% | 1 | 199.75 | Township |
| Ogallah township | 4 | 162 | 162 | 0.62% | 1 | 143.90 | Township |
| Collyer | 5 | 91 | 95 | -1.09% | 389 | 0.23 | City |
| Riverside township | 6 | 85 | 87 | 0% | 1 | 114.97 | Township |
| Glencoe township | 7 | 63 | 67 | -1.56% | 2 | 35.95 | Township |
| Wilcox township | 8 | 63 | 64 | 0% | 1 | 115.29 | Township |
| Ogallah | 9 | 15 | 10 | 7.14% | 9 | 1.60 | CDP |
WaKeeney township is the largest city in Trego County, with a population of 2,022.
Ogallah is the smallest city in Trego County.
There are 9 cities in Trego County, Kansas.