County facts · Population · October 25, 2026

Arizona Population by County, 2025 Census Estimates

Arizona population by county: July 2025 Census estimates for all 15 counties, change since 2020, density, and a link to each official parcel map.

Looking for Arizona population by county? The Census Bureau estimates that Arizona had 7,623,818 residents on July 1, 2025, spread across 15 counties. Maricopa County is the most populous, with 4,689,558 people (62% of the state), and Greenlee County is the least populous, with 9,312.

The table below lists every county with its 2025 estimate, its April 2020 starting point, the change, people per square mile, and a link to its official parcel viewer.

Arizona population at a glance

• Counties: 15
• Statewide, July 1, 2025: 7,623,818 (April 1, 2020 estimates base: 7,158,104; change +465,714, +6.5%)
• Most populous: Maricopa County (4,689,558); least populous: Greenlee County (9,312)
• Median county: about 126,332 residents (half of the counties are smaller)
• The 5 largest counties hold 89% of all Arizona residents
• Counties with 1,000,000+ residents: 2 · 100,000+: 9 · under 10,000: 1
• Statewide density: about 67 people per square mile of land

Arizona population by county, July 2025 (all 15)

Percent change runs from the April 1, 2020 estimates base to July 1, 2025. People per square mile is the July 2025 estimate divided by the county's land area in the Census Bureau's 2020 Gazetteer file, so lakes and bays are left out.

How Arizona's population is spread out

Grouping the counties by size shows how concentrated the state is:

4 counties with at least 250,000 residents hold 86% of the state's population.

Most and least densely populated

The most crowded counties by people per square mile of land:

1. Maricopa County: 510 per sq mi (4,689,558 people on 9,202 sq mi)
2. Pima County: 117 per sq mi (1,074,685 people on 9,189 sq mi)
3. Pinal County: 101 per sq mi (539,380 people on 5,366 sq mi)
4. Yuma County: 41 per sq mi (224,449 people on 5,514 sq mi)
5. Santa Cruz County: 40 per sq mi (50,020 people on 1,236 sq mi)

The most thinly settled:

1. La Paz County: 3.7 per sq mi (16,711 people on 4,497 sq mi)
2. Greenlee County: 5.1 per sq mi (9,312 people on 1,842 sq mi)
3. Apache County: 5.8 per sq mi (64,445 people on 11,198 sq mi)
4. Coconino County: 7.8 per sq mi (144,368 people on 18,616 sq mi)
5. Graham County: 8.7 per sq mi (40,157 people on 4,622 sq mi)

About these numbers

• They are estimates. Between censuses the Census Bureau's Population Estimates Program updates county totals each year from births, deaths and migration records. The next full count is the 2030 census.
• The base is April 1, 2020. The estimates start from an April 1, 2020 "estimates base" built from the 2020 census, which is why it is slightly different from the published census count.
• Each new release revises the past. A newer vintage can change earlier years as well, so compare numbers from the same release, as this page does.
• Statewide total. The counties add up exactly to the statewide figure of 7,623,818 in the same file.

Using population numbers in a land search

• Big counties, busy offices. In the most populous counties, parcel maps and deed records are usually online and searchable, but recording and permit offices are busier. Allow for that if you are on a deadline.
• Small counties, fewer sales. In counties with only a few thousand people, land changes hands less often, so there are fewer recent sales to compare a price with. Recorded deeds and the local assessor's sales records are the best source.
• Density hints at lot size. A low people-per-square-mile figure usually means farms, ranches and timber tracts; a high one means subdivided lots. The parcel viewer shows the actual parcel lines.
• Check the official map. Use the parcel viewer link in the table for boundaries, parcel numbers and owner names, then confirm anything important with the local assessor and the office that records deeds.

Related guides

• Fastest growing counties in Arizona
• Largest counties in Arizona
• Arizona county GIS websites by viewer
• Arizona plat maps
• Arizona landowner maps for hunting
• Most populous counties in the US
• Where people are moving in the US

More: All Arizona counties on Platbookmapper

Sources

• U.S. Census Bureau, Population Estimates Program, county totals, Vintage 2025 (April 1, 2020 estimates base and July 1, 2020–2025 estimates, with components of change). Statewide totals are the sum of the counties and match the file's state row.
• U.S. Census Bureau Gazetteer files, 2020 county land and water area (for people per square mile).
• Platbookmapper county GIS directory (live data file behind our county pages, pulled October 25, 2026) for each official parcel viewer.