| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Corvallis | 1 | 62,223 | 58,356 | 1.18% | 4,283 | 15 | City |
| Philomath | 2 | 5,790 | 5,342 | 1.6% | 2,805 | 2 | City |
| Millersburg | 3 | 3,693 | 3,104 | 3.07% | 891 | 4 | City |
| Adair Village | 4 | 1,016 | 986 | 0.59% | 2,288 | 0 | City |
| Monroe | 5 | 670 | 646 | 0.75% | 1,301 | 1 | City |
Corvallis is the largest city in Benton County, with a population of 62,223.
Monroe is the smallest city in Benton County, with a population of 670.
There are 5 cities in Benton County, Oregon.