The largest county in Oregon
There are two right answers. By land area it is Harney County; by population it is Multnomah County. Which one you want depends on what you meant by largest.
Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025. Retrieved 30 August 2026.
By land area
| Rank | Name | Land area | Population |
|---|---|---|---|
| 1 | Harney County | 10,134 sq mi | 7,380 |
| 2 | Malheur County | 9,888 sq mi | 32,261 |
| 3 | Lake County | 8,139 sq mi | 8,187 |
| 4 | Klamath County | 5,950 sq mi | 70,274 |
| 5 | Douglas County | 5,036 sq mi | 111,951 |
| 6 | Lane County | 4,554 sq mi | 381,584 |
| 7 | Grant County | 4,528 sq mi | 7,075 |
| 8 | Umatilla County | 3,215 sq mi | 81,119 |
| 9 | Wallowa County | 3,146 sq mi | 7,595 |
| 10 | Baker County | 3,068 sq mi | 16,658 |
By population
| Rank | Name | Population | Density |
|---|---|---|---|
| 1 | Multnomah County | 795,391 | 1,845 per sq mi |
| 2 | Washington County | 611,708 | 845 per sq mi |
| 3 | Clackamas County | 426,280 | 228 per sq mi |
| 4 | Lane County | 381,584 | 83.8 per sq mi |
| 5 | Marion County | 355,777 | 301 per sq mi |
| 6 | Jackson County | 221,795 | 79.7 per sq mi |
| 7 | Deschutes County | 213,072 | 70.6 per sq mi |
| 8 | Linn County | 132,843 | 58.0 per sq mi |
| 9 | Douglas County | 111,951 | 22.2 per sq mi |
| 10 | Yamhill County | 110,024 | 154 per sq mi |
And the smallest
More on Oregon
Rebuilt from source data 30 August 2026. How these figures are produced.