5 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Ontario | 1 | 12,052 | 11,767 | 0.4% | 2,014 | 6 | City |
| Nyssa | 2 | 3,298 | 3,211 | 0.46% | 2,128 | 2 | City |
| Vale | 3 | 2,134 | 1,903 | 1.86% | 1,835 | 1 | City |
| Adrian | 4 | 162 | 155 | 0.62% | 664 | 0 | City |
| Jordan Valley | 5 | 140 | 134 | 0.72% | 67 | 2 | City |
Ontario is the largest city in Malheur County, with a population of 12,052.
Jordan Valley is the smallest city in Malheur County, with a population of 140.
There are 5 cities in Malheur County, Oregon.