6 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Kennewick | 1 | 85,940 | 83,984 | 0.46% | 3,015 | 28.50 | City |
| Richland | 2 | 65,656 | 60,908 | 1.47% | 1,647 | 39.87 | City |
| West Richland | 3 | 19,834 | 16,388 | 3.6% | 897 | 22.11 | City |
| Prosser | 4 | 6,518 | 6,138 | 1.18% | 1,261 | 5.17 | City |
| Finley | 5 | 5,807 | 5,858 | -0.24% | 502 | 11.56 | CDP |
| Benton City | 6 | 3,902 | 3,479 | 2.23% | 1,568 | 2.49 | City |
Kennewick is the largest city in Benton County, with a population of 85,940.
Benton City is the smallest city in Benton County.
There are 6 cities in Benton County, Washington.