11 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Cortland | 1 | 17,116 | 17,515 | -0.46% | 4,395 | 3.89 | City |
| Cortlandville | 2 | 8,096 | 8,403 | -0.65% | 163 | 49.72 | Town |
| Homer | 3 | 5,985 | 6,289 | -0.96% | 119 | 50.22 | Town |
| Homer | 4 | 3,006 | 3,183 | -1.15% | 1,562 | 1.93 | Village |
| Virgil | 5 | 2,380 | 2,424 | -0.13% | 50 | 47.37 | Town |
| Marathon | 6 | 1,932 | 2,032 | -0.97% | 77 | 24.94 | Town |
| Preble | 7 | 1,292 | 1,357 | -0.77% | 48 | 26.84 | Town |
| Scott | 8 | 1,040 | 1,074 | -0.67% | 47 | 22.24 | Town |
| Solon | 9 | 1,016 | 1,064 | -1.07% | 34 | 29.65 | Town |
| McGraw | 10 | 955 | 1,010 | -1.14% | 968 | 0.99 | Village |
| Marathon | 11 | 863 | 913 | -1.15% | 764 | 1.13 | Village |
Cortland is the largest city in Cortland County, with a population of 17,116.
Marathon is the smallest city in Cortland County.
There are 11 cities in Cortland County, New York.