8 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Nampa | 1 | 125,310 | 101,430 | 3.28% | 3,474 | 36 | City |
| Caldwell | 2 | 79,260 | 60,743 | 4.05% | 3,121 | 25 | City |
| Middleton | 3 | 12,811 | 9,567 | 4.41% | 1,936 | 7 | City |
| Parma | 4 | 2,246 | 2,101 | 1.08% | 2,078 | 1 | City |
| Wilder | 5 | 1,789 | 1,596 | 1.82% | 2,454 | 1 | City |
| Greenleaf | 6 | 782 | 811 | -0.64% | 1,016 | 1 | City |
| Melba | 7 | 652 | 570 | 2.19% | 1,427 | 0 | City |
| Notus | 8 | 603 | 611 | -0.17% | 613 | 1 | City |
Nampa is the largest city in Canyon County, with a population of 125,310.
Notus is the smallest city in Canyon County, with a population of 603.
There are 8 cities in Canyon County, Idaho.