What are the largest counties in Arizona?

Maricopa County is the largest county in Arizona, with 4,689,558 residents in 2025 (Census PEP). Pima County (1,074,685) and Pinal County (539,380) come next.

Data as of 2025 · updated November 5, 2026

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All 15 ranked Arizona counties

Arizona counties ranked by population
Rank	County	Residents 2025	Change 2020–25
1	Maricopa County	4,689,558	+5.5%
2	Pima County	1,074,685	+2.8%
3	Pinal County	539,380	+25.4%
4	Yavapai County	252,552	+6.5%
5	Mohave County	228,102	+6.5%
6	Yuma County	224,449	+9.2%
7	Coconino County	144,368	−0.6%
8	Cochise County	126,332	+0.6%
9	Navajo County	109,946	+3.0%
10	Apache County	64,445	−2.2%
11	Gila County	53,801	+0.9%
12	Santa Cruz County	50,020	+4.8%
13	Graham County	40,157	+4.0%
14	La Paz County	16,711	+0.9%
15	Greenlee County	9,312	−2.3%

How this is ranked

The Census Bureau's July 1 resident population estimates for 2025, largest first, with the change since 2020. Counties with fewer than 1,000 residents are not ranked. Areas without an estimate for the same year as the others are not ranked.

Source: U.S. Census Bureau, Population Estimates Program (Vintage 2025). Figures come from public federal statistics and are informational only, not investment advice. Check the source before relying on a number. Methodology: how ranks and figures are built.

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Questions

What is the largest county in Arizona?

Maricopa County is the largest county in Arizona, with 4,689,558 residents in 2025 (Census PEP). Pima County (1,074,685) and Pinal County (539,380) come next.

How is this ranking calculated?

More rankings for Arizona

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