Data / Rankings / Population / Counties in Arizona

Counties in Arizona by population

Maricopa County had the highest population of 15 counties in 2021, at 4.5 million. Greenlee County had the lowest, at 9,398. The median was 126,215 and the figure for Arizona was 7.27 million. Source: the U.S. Census Bureau.

Highest4,500,059Maricopa County
Lowest9,398Greenlee County
Median126,21515 counties
Arizona7,274,022History

All counties, 2021

CSVChart (SVG)

Maricopa CountyMaricopa County: 4,500,059 persons4,500,059Pima CountyPima County: 1,049,271 persons1,049,271Pinal CountyPinal County: 449,128 persons449,128Yavapai CountyYavapai County: 242,454 persons242,454Mohave CountyMohave County: 217,232 persons217,232Yuma CountyYuma County: 207,654 persons207,654Coconino CountyCoconino County: 142,851 persons142,851Cochise CountyCochise County: 126,215 persons126,215Navajo CountyNavajo County: 107,679 persons107,679Apache CountyApache County: 65,339 persons65,339Gila CountyGila County: 53,522 persons53,522Santa Cruz CountySanta Cruz County: 47,956 persons47,956Graham CountyGraham County: 38,906 persons38,906La Paz CountyLa Paz County: 16,358 persons16,358Greenlee CountyGreenlee County: 9,398 persons9,398
persons. Source: U.S. Census Bureau. Retrieved 2026-10-08.

Full ranking

RankCounties2021
persons		Change on 2020
1Maricopa County4,500,059+1.2%
2Pima County1,049,271+0.4%
3Pinal County449,128+4.4%
4Yavapai County242,454+2.2%
5Mohave County217,232+1.4%
6Yuma County207,654+1%
7Coconino County142,851-1.6%
8Cochise County126,215+0.5%
9Navajo County107,679+0.9%
10Apache County65,339-0.9%
11Gila County53,522+0.3%
12Santa Cruz County47,956+0.5%
13Graham County38,906+0.7%
14La Paz County16,358-1.2%
15Greenlee County9,398-1.4%

Other periods

About this ranking

Resident population. Spain and the EU: 1 January, with Spanish figures from the official municipal register (Padrón). United States: Census Bureau population estimates for 1 July. Other countries and the World: World Bank mid-year estimates, which count all residents regardless of legal status or citizenship.

For Denmark, Statistics Denmark counts the registered resident population on 1 January. Greenland and the Faroe Islands are excluded. The annual series selects the first-quarter reference date from FOLK1A. The World Bank series exists for every country, so use it (through compare) to rank countries on one basis.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

U.S. Census Bureau. Annual estimates of the resident population for the United States, states and counties, 1 July (Population Estimates Program). https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-08.

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Questions

Which county has the highest population?

Maricopa County, with 4.5 million in 2021, according to the U.S. Census Bureau.

Which county has the lowest population?

Greenlee County, with 9,398 in 2021.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, Annual estimates of the resident population for the United States, states and counties, 1 July (Population Estimates Program). Retrieved 2026-10-08.

Population: other rankings

Counties in Arizona: more rankings