What County Is Tucson, AZ In?
The short answer: Pima County — and Tucson is its county seat.
Tucson, Arizona is in Pima County. Tucson is also the county seat, so the Pima County Superior Court, Recorder’s Office, Assessor and Board of Supervisors are all based in downtown Tucson. The entire city lies inside Pima County — no part of Tucson crosses into a neighbouring county. For deeds, property tax, voter registration or court filings tied to a Tucson address, Pima County is the jurisdiction you want.
Pima County is Arizona’s second most populous county, with 1,043,433 residents in the 2020 Census, behind only Maricopa County. It is also one of the state’s four original counties, created in 1864 out of land acquired in the Gadsden Purchase. At roughly 9,189 square miles it is larger than New Jersey, running from the Tohono O’odham Nation and Organ Pipe Cactus National Monument in the west across to the Rincon Mountains east of Tucson, and south to the Mexican border.
Why People Ask “What County Is Tucson In?”
There is no Tucson County, and the county’s actual name offers no clue: Pima County is named for the Akimel O’odham, historically called the Pima by Spanish missionaries. Because the name and the city do not match, the lookup is genuinely non-obvious for anyone outside Arizona — and it comes up constantly on forms, insurance quotes, jury summonses, school-district checks and property searches.
The other trap is the edge of the metro area. Marana, on Tucson’s northwest side, straddles the Pima–Pinal county line, so two houses on the same road can sit in different counties. Head southeast and Benson and Sierra Vista are in Cochise County; head south to Nogales and you are in Santa Cruz County. Only the places listed as Pima County below are administered from Tucson.
Pima County at a Glance
County Information
City of Tucson
Which County Is Each Town Around Tucson In?
Most of metropolitan Tucson is Pima County, but the ring of towns beyond it is not. Check a specific place here.
| Place | Population (2020) | County | Notes |
|---|---|---|---|
| Tucson | 542,629 | Pima County | County seat |
| Casas Adobes | 71,020 | Pima County | Unincorporated, northwest of Tucson |
| Catalina Foothills | 50,796 | Pima County | Unincorporated, north of Tucson |
| Oro Valley | 47,070 | Pima County | North of Tucson |
| Marana | 51,908 | Pima & Pinal | Straddles the county line |
| Sahuarita | 34,134 | Pima County | South of Tucson |
| Green Valley | 21,391 | Pima County | Unincorporated retirement community |
| Vail | 14,562 | Pima County | Southeast of Tucson |
| South Tucson | 4,652 | Pima County | Separate city enclosed by Tucson |
| Ajo | 3,304 | Pima County | Far west, near Organ Pipe |
| Sierra Vista | 45,308 | Cochise County | Southeast — different county |
| Nogales | 19,770 | Santa Cruz County | On the Mexican border — different county |
| Casa Grande | 53,658 | Pinal County | Halfway to Phoenix — different county |
What Else Is in Pima County?
Pima County holds a striking share of southern Arizona’s landmarks. Both districts of Saguaro National Park sit inside it, one on each side of Tucson — the Tucson Mountain District to the west and the Rincon Mountain District to the east. Kitt Peak National Observatory, Organ Pipe Cactus National Monument, the Arizona-Sonora Desert Museum, Mission San Xavier del Bac and the Tohono O’odham Nation, the second-largest tribal land base in the United States, are all in Pima County too. The county also contains Mount Lemmon, which at 9,159 feet lets you drive from saguaro desert to conifer forest in about an hour.
For the full county profile, see the Pima County map, compare it against all 15 Arizona counties, or find any other place on the map of Arizona cities and towns.
Frequently Asked Questions
No. Arizona has 15 counties and none is named Tucson. Tucson is the seat of Pima County, named after the Akimel O’odham people. Pima is one of the four original counties created when the Arizona Territory was organised in 1864.
Casa Grande, Eloy and Picacho are in Pinal County. Benson, Sierra Vista, Tombstone and Willcox are in Cochise County. Nogales and Rio Rico are in Santa Cruz County. Marana is split between Pima and Pinal counties.
About 9,189 square miles — the sixth largest county in Arizona by area and bigger than New Jersey. It runs roughly 130 miles east to west and touches the Mexican border along its southern edge.
Yes — both halves of it. The Tucson Mountain District lies west of the city and the Rincon Mountain District lies east, and both are within Pima County. Kitt Peak National Observatory and Organ Pipe Cactus National Monument are also in the county.
Pima County, headquartered in downtown Tucson, handles deeds and voter registration through the Recorder’s Office, property valuation through the Assessor, property tax through the Treasurer, and court filings through the Clerk of the Superior Court. City services such as water and permits come from the City of Tucson.
Last reviewed on August 27, 2026.