5 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Corvallis | 1 | 63,817 | 58,345 | 1.45% | 4,392 | 15 | City |
| Philomath | 2 | 6,021 | 5,342 | 1.91% | 2,917 | 2 | City |
| Millersburg | 3 | 3,759 | 3,104 | 2.99% | 907 | 4 | City |
| Adair Village | 4 | 1,049 | 986 | 1.06% | 2,363 | 0 | City |
| Monroe | 5 | 693 | 645 | 1.17% | 1,346 | 1 | City |
Corvallis is the largest city in Benton County, with a population of 63,817.
Monroe is the smallest city in Benton County, with a population of 693.
There are 5 cities in Benton County, Oregon.