8 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Nampa | 1 | 122,906 | 101,310 | 3.64% | 3,535 | 34.77 | City |
| Caldwell | 2 | 73,466 | 60,641 | 3.62% | 3,124 | 23.52 | City |
| Middleton | 3 | 11,987 | 9,559 | 4.23% | 1,961 | 6.11 | City |
| Parma | 4 | 2,185 | 2,094 | 0.83% | 2,021 | 1.08 | City |
| Wilder | 5 | 1,745 | 1,595 | 1.75% | 2,394 | 0.73 | City |
| Greenleaf | 6 | 776 | 811 | -0.89% | 1,008 | 0.77 | City |
| Notus | 7 | 601 | 608 | -0.17% | 1,616 | 0.37 | City |
| Melba | 8 | 598 | 573 | 0.84% | 1,309 | 0.46 | City |
Nampa is the largest city in Canyon County, with a population of 122,906.
Melba is the smallest city in Canyon County.
There are 8 cities in Canyon County, Idaho.