The largest county in Arizona
There are two right answers. By land area it is Coconino County; by population it is Maricopa 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 | Coconino County | 18,616 sq mi | 144,368 |
| 2 | Mohave County | 13,332 sq mi | 228,102 |
| 3 | Apache County | 11,198 sq mi | 64,445 |
| 4 | Navajo County | 9,949 sq mi | 109,946 |
| 5 | Maricopa County | 9,202 sq mi | 4,689,558 |
| 6 | Pima County | 9,189 sq mi | 1,074,685 |
| 7 | Yavapai County | 8,123 sq mi | 252,552 |
| 8 | Cochise County | 6,210 sq mi | 126,332 |
| 9 | Yuma County | 5,514 sq mi | 224,449 |
| 10 | Pinal County | 5,367 sq mi | 539,380 |
By population
| Rank | Name | Population | Density |
|---|---|---|---|
| 1 | Maricopa County | 4,689,558 | 510 per sq mi |
| 2 | Pima County | 1,074,685 | 117 per sq mi |
| 3 | Pinal County | 539,380 | 101 per sq mi |
| 4 | Yavapai County | 252,552 | 31.1 per sq mi |
| 5 | Mohave County | 228,102 | 17.1 per sq mi |
| 6 | Yuma County | 224,449 | 40.7 per sq mi |
| 7 | Coconino County | 144,368 | 7.8 per sq mi |
| 8 | Cochise County | 126,332 | 20.3 per sq mi |
| 9 | Navajo County | 109,946 | 11.1 per sq mi |
| 10 | Apache County | 64,445 | 5.8 per sq mi |
And the smallest
More on Arizona
Rebuilt from source data 30 August 2026. How these figures are produced.