County outline
Where Pima County is located
Area breakdown
Land accounts for 100% of Pima County’s measured area and water for 0%. Its combined area converts to 23,803.7 square kilometers or approximately 5,882,026 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 9,188.692 | 23,798.603 | 5,880,762.9 |
| Water | 1.974 | 5.113 | 1,263.4 |
| Total | 9,190.666 | 23,803.716 | 5,882,026.2 |
How Pima County compares
By original Census land area, Pima County ranks #6 of 15 in Arizona and #29 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 1.48 times the Arizona county-equivalent median of 6,209.9 square miles. It accounts for 8.1% of the combined county land area in the state.
See the complete Arizona ranking · What counts as a county equivalent?
Population and density of Pima County
The Census Bureau estimates that 1,074,685 people lived in Pima County on July 1, 2025. That ranks #44 of 3,222 county equivalents nationally and #2 of 15 in Arizona. Since the April 1, 2020 estimates base of 1,043,431, the population has grown by 31,254 (+3%), compared with +6.5% for Arizona as a whole.
With 9,188.7 square miles of land, that is 117 people per square mile (45 per km²), placing Pima County #893 nationally for density and #2 in Arizona. The median county equivalent has 47 people per square mile; the Arizona median is 17. Put another way, there are about 5.5 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 1,045,245 | 1,049,271 | 1,058,224 | 1,065,239 | 1,073,456 | 1,074,685 |
| Change | — | +4,026 | +8,953 | +7,015 | +8,217 | +1,229 |
U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.
Cities and towns in Pima County
5 incorporated places lie at least partly in Pima County. Together they are home to 704,125 people (65.5%); the other 370,560 (34.5%) live outside any incorporated place, in unincorporated communities and rural areas.
The largest is Tucson city, with 548,371 residents in the county. Among places with at least 1,000 residents in 2020, Marana town grew fastest since then (+26.2%).
| Incorporated place | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Tucson cityCounty seat | 548,371 | +1.1% | 242.9 |
| Marana townAlso in 1 other county | 65,523 | +26.2% | 121.7 |
| Oro Valley town | 48,085 | +2.2% | 35.1 |
| Sahuarita town | 37,694 | +10.6% | 31.7 |
| South Tucson city | 4,452 | −3.5% | 1.027 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Pima County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.
Metropolitan area
Pima County is a central county of the Tucson, AZ Metropolitan Statistical Area. Pima County is the area’s only county equivalent, so the metro area has the same 9,188.7 square miles of land. By combined land it ranks #8 of 393 metropolitan areas, and #53 by population. It belongs to the Tucson-Nogales, AZ Combined Statistical Area.
ZIP codes
56 ZIP Code Tabulation Areas have land in Pima County; 51 of them have most of their land inside the county, and the others mainly cover neighboring areas.
8532185341856018560285611856148561985622856298563385634856378563985641856458565385654856588570185704857058570685707857088570985710857118571285713857148571585716857188571985721857238572485726857308573485735857368573785739857418574285743857458574685747857488574985750857558575685757
ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.
Counties bordering Pima County
Pima County shares a land border with 6 county equivalents. It has more land than 5 of them. The largest neighbor is Maricopa County (9,202 mi²) and the smallest is Santa Cruz County (1,236.3 mi²). Together with its neighbors, Pima County forms a block of 41,339.2 mi² of land, of which it holds 22.2%.
| Bordering county equivalent | Land mi² | Size vs. Pima | Compare |
|---|---|---|---|
| Maricopa County | 9,202 | about the same | Compare |
| Cochise County | 6,209.9 | 1.5× smaller | Compare |
| Yuma County | 5,513.8 | 1.7× smaller | Compare |
| Pinal County | 5,366.7 | 1.7× smaller | Compare |
| Graham County | 4,621.9 | 2× smaller | Compare |
| Santa Cruz County | 1,236.3 | 7.4× smaller | Compare |
How big is Pima County compared with U.S. states?
Pima County has more land than 7 of the 50 states. It is about 1 times the land area of New Hampshire (8,954 mi²), while Vermont, the next larger state, has 1 times as much land (9,217.3 mi²). Arizona’s county land could hold about 12 areas the size of Pima County.
Another way to picture it: the same land area would fill a square about 95.9 miles (154.3 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.
State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.
What stands out about Pima County?
Pima County has more land than 3,193 of the other 3,221 county equivalents in the dataset.
A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.
Does including water change its rank?
Using land plus water places Pima County at #35 nationally by total area, 6 places farther from the top than its land rank. Other county equivalents gain more area when their water measurements are included.
Its water share is 0%, compared with a national county-equivalent median of 1.2% — 1.1 percentage points lower. This describes the statistical geography’s land/water mix, not flood exposure or developable land.
Closest positions in the national land ranking
These entries sit immediately beside Pima County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #28 | Maricopa County, Arizona | 9,202 | Compare |
| #29 | Pima County, Arizona | 9,188.7 | This county |
| #30 | Fremont County, Wyoming | 9,183.6 | Compare |
Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.
Representative coordinates
The Census internal point is 32.128038, -111.783657. It represents a location inside the geography; it is not necessarily the centroid or the address of a courthouse.
Source and precision
U.S. Census Bureau, 2026 Gazetteer Files, Counties. Original ALAND: 23,798,602,499 m²; AWATER: 5,112,016 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.
Common questions
How big is Pima County?
Pima County, Arizona has 9,188.7 square miles (23,798.6 km²) of land and 1.974 square miles of water, for a total area of 9,190.7 square miles. It ranks #29 of 3,222 U.S. county equivalents by land area.
Is Pima County the largest county in Arizona?
No. Pima County ranks #6 of 15 in Arizona by land area. The largest is Coconino County, with 18,616.4 square miles of land.
What counties border Pima County?
Pima County shares a land border with Pinal County, Santa Cruz County, Maricopa County, Cochise County, Yuma County, and Graham County.
What is the population of Pima County?
The Census Bureau estimates Pima County had 1,074,685 residents on July 1, 2025, ranking #44 of 3,222 county equivalents. That is 117 people per square mile of land.
What is the county seat of Pima County?
The county seat of Pima County is Tucson.
What cities and towns are in Pima County?
Pima County has 5 incorporated places. The most populous are Tucson city, Marana town, Oro Valley town, Sahuarita town, and South Tucson city; 370,560 residents live outside any incorporated place.
Is Pima County part of a metropolitan area?
Yes. It is a central county of the Tucson, AZ Metropolitan Statistical Area.
How many ZIP codes are in Pima County?
56 ZIP Code Tabulation Areas have land in Pima County, and 51 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does Pima County compare with U.S. states?
It has more land than 7 of the 50 states, including New Hampshire (8,954 square miles of land).
How many acres of land are in Pima County?
The land measurement converts to approximately 5,880,763 acres. Including water, total area is approximately 5,882,026 acres. One square mile equals 640 acres.
Why might another source show a different area?
Check whether it reports land or total area, its Census vintage, and its rounding. Our guide explains how to reconcile county area figures.
Can this establish a property boundary?
No. Statistical measurements and generalized maps do not establish property lines. Consult the relevant local surveying or land-records authority.