44 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Emporia | 1 | 24,418 | 24,140 | 0.26% | 1,983 | 12 | City |
| Emporia | 2 | 24,418 | 24,096 | 0.26% | 1,983 | 12 | City |
| Americus | 3 | 1,380 | 1,360 | 0.8% | 16 | 87 | Township |
| Americus | 4 | 1,380 | 1,356 | 0.8% | 16 | 87 | Township |
| Center | 5 | 1,131 | 1,100 | 1.25% | 10 | 119 | Township |
| Center | 6 | 1,131 | 1,097 | 1.25% | 10 | 119 | Township |
| Jackson | 7 | 974 | 948 | 0.93% | 11 | 87 | Township |
| Jackson | 8 | 974 | 945 | 0.93% | 11 | 87 | Township |
| Emporia | 9 | 964 | 949 | 0.73% | 18 | 52 | Township |
| Emporia | 10 | 964 | 946 | 0.73% | 18 | 52 | Township |
| Fremont | 11 | 859 | 836 | 1.06% | 12 | 71 | Township |
| Fremont | 12 | 859 | 834 | 1.06% | 12 | 71 | Township |
| Pike | 13 | 845 | 810 | 1.2% | 16 | 53 | Township |
| Pike | 14 | 845 | 810 | 1.2% | 16 | 53 | Township |
| Americus | 15 | 779 | 779 | 0% | 719 | 1 | City |
| Americus | 16 | 779 | 777 | 0% | 719 | 1 | City |
| Elmendaro | 17 | 754 | 734 | 0.8% | 8 | 99 | Township |
| Elmendaro | 18 | 754 | 732 | 0.8% | 8 | 99 | Township |
| Olpe | 19 | 531 | 517 | 0.57% | 756 | 1 | City |
| Olpe | 20 | 531 | 516 | 0.57% | 756 | 1 | City |
| Agnes City | 21 | 426 | 416 | 0.95% | 4 | 107 | Township |
| Agnes City | 22 | 426 | 415 | 0.95% | 4 | 107 | Township |
| Reading | 23 | 422 | 412 | 0.96% | 6 | 67 | Township |
| Reading | 24 | 422 | 411 | 0.96% | 6 | 67 | Township |
| Hartford | 25 | 366 | 356 | 0.55% | 924 | 0 | City |
| Hartford | 26 | 366 | 355 | 0.55% | 924 | 0 | City |
| Ivy | 27 | 247 | 237 | 1.65% | 7 | 34 | Township |
| Ivy | 28 | 247 | 237 | 1.65% | 7 | 34 | Township |
| Waterloo | 29 | 246 | 235 | 1.65% | 4 | 59 | Township |
| Waterloo | 30 | 246 | 234 | 1.65% | 4 | 59 | Township |
| Neosho Rapids | 31 | 240 | 235 | 0.42% | 475 | 1 | City |
| Neosho Rapids | 32 | 240 | 234 | 0.42% | 475 | 1 | City |
| Reading | 33 | 184 | 182 | 0% | 864 | 0 | City |
| Reading | 34 | 184 | 182 | 0% | 864 | 0 | City |
| Allen | 35 | 166 | 161 | 0.61% | 601 | 0 | City |
| Allen | 36 | 166 | 161 | 0.61% | 601 | 0 | City |
| Admire | 37 | 138 | 133 | 0.73% | 427 | 0 | City |
| Admire | 38 | 138 | 133 | 0.73% | 427 | 0 | City |
| Allen | 39 | 101 | 112 | -2.88% | 3 | 36 | Township |
| Allen | 40 | 101 | 111 | -2.88% | 3 | 36 | Township |
| Bushong | 41 | 28 | 28 | 0% | 184 | 0 | City |
| Bushong | 42 | 28 | 28 | 0% | 184 | 0 | City |
| Allen | 43 | 15 | 15 | 0% | 0.00 | 35 | Township |
| Allen | 44 | 15 | 15 | 0% | 0.00 | 35 | Township |
Emporia is the largest city in Lyon County, with a population of 24,418.
Allen is the smallest city in Lyon County, with a population of 15.
There are 44 cities in Lyon County, Kansas.