22 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Emporia | 1 | 24,483 | 24,096 | 0.27% | 1,979 | 12 | City |
| Americus | 2 | 1,391 | 1,356 | 0.8% | 16 | 87 | Township |
| Center | 3 | 1,145 | 1,097 | 1.24% | 10 | 119 | Township |
| Jackson | 4 | 983 | 945 | 0.92% | 11 | 87 | Township |
| Emporia | 5 | 971 | 946 | 0.73% | 19 | 52 | Township |
| Fremont | 6 | 868 | 834 | 1.05% | 12 | 71 | Township |
| Pike | 7 | 855 | 810 | 1.18% | 16 | 53 | Township |
| Americus | 8 | 780 | 777 | 0.13% | 720 | 1 | City |
| Elmendaro | 9 | 760 | 732 | 0.8% | 8 | 99 | Township |
| Olpe | 10 | 534 | 516 | 0.56% | 761 | 1 | City |
| Agnes City | 11 | 430 | 415 | 0.94% | 4 | 107 | Township |
| Reading | 12 | 426 | 411 | 0.95% | 6 | 67 | Township |
| Hartford | 13 | 368 | 355 | 0.55% | 929 | 0 | City |
| Ivy | 14 | 251 | 237 | 1.62% | 7 | 34 | Township |
| Waterloo | 15 | 250 | 234 | 1.63% | 4 | 59 | Township |
| Neosho Rapids | 16 | 241 | 234 | 0.42% | 477 | 1 | City |
| Reading | 17 | 185 | 182 | 0.54% | 869 | 0 | City |
| Allen | 18 | 167 | 161 | 0.6% | 605 | 0 | City |
| Admire | 19 | 139 | 133 | 0.72% | 430 | 0 | City |
| Allen | 20 | 98 | 111 | -2.97% | 3 | 36 | Township |
| Bushong | 21 | 28 | 28 | 0% | 184 | 0 | City |
| Allen | 22 | 15 | 15 | 0% | 0.00 | 35 | Township |
Emporia is the largest city in Lyon County, with a population of 24,483.
Allen is the smallest city in Lyon County, with a population of 15.
There are 22 cities in Lyon County, Kansas.