5 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Corvallis | 1 | 62,905 | 58,345 | 1.47% | 4,330 | 15 | City |
| Philomath | 2 | 5,908 | 5,342 | 1.95% | 2,862 | 2 | City |
| Millersburg | 3 | 3,650 | 3,104 | 3.08% | 880 | 4 | City |
| Adair Village | 4 | 1,038 | 986 | 0.97% | 2,338 | 0 | City |
| Monroe | 5 | 685 | 645 | 1.18% | 1,330 | 1 | City |
Corvallis is the largest city in Benton County, with a population of 62,905.
Monroe is the smallest city in Benton County, with a population of 685.
There are 5 cities in Benton County, Oregon.