| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Nampa | 1 | 124,426 | 101,406 | 3.36% | 3,450 | 36 | City |
| Caldwell | 2 | 79,746 | 60,708 | 4.07% | 3,140 | 25 | City |
| Middleton | 3 | 13,145 | 9,573 | 4.33% | 1,987 | 7 | City |
| Parma | 4 | 2,228 | 2,094 | 1.13% | 2,061 | 1 | City |
| Wilder | 5 | 1,767 | 1,596 | 1.9% | 2,424 | 1 | City |
| Greenleaf | 6 | 783 | 811 | -0.63% | 1,017 | 1 | City |
| Melba | 7 | 643 | 570 | 2.06% | 1,407 | 0 | City |
| Notus | 8 | 604 | 613 | -0.17% | 614 | 1 | City |
Nampa is the largest city in Canyon County, with a population of 124,426.
Notus is the smallest city in Canyon County, with a population of 604.
There are 8 cities in Canyon County, Idaho.