5 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Kennewick | 1 | 88,092 | 84,000 | 0.78% | 3,091 | 29 | City |
| Richland | 2 | 66,112 | 60,892 | 1.33% | 1,557 | 42 | City |
| West Richland | 3 | 20,036 | 16,387 | 3.13% | 906 | 22 | City |
| Prosser | 4 | 6,737 | 6,146 | 1.49% | 1,304 | 5 | City |
| Benton City | 5 | 4,071 | 3,486 | 2.47% | 1,636 | 2 | City |
Kennewick is the largest city in Benton County, with a population of 88,092.
Benton City is the smallest city in Benton County, with a population of 4,071.
There are 5 cities in Benton County, Washington.