Arizona County Government Structure: Boards, Officers, and Functions

Arizona operates 15 counties, each functioning as an administrative arm of the state rather than an independent sovereign entity. This page covers how those counties are organized, who holds authority within them, what elected and appointed officers do, and where county jurisdiction ends and other governance begins. The structure is more consequential than it might first appear — counties administer elections, assess property, operate courts, and deliver public health services for roughly 7.4 million residents (U.S. Census Bureau, 2020 Decennial Census).

Definition and scope

Arizona counties exist under Article XII of the Arizona Constitution, which establishes them as political subdivisions of the state. The critical word is subdivision — counties do not derive independent governing authority. They exercise powers granted by the state legislature through Title 11 of the Arizona Revised Statutes, which runs to dozens of chapters covering everything from county jails to flood control districts.

There are exactly 15 counties in Arizona, ranging from Maricopa County — the fourth-most-populous county in the United States with over 4.4 million residents — down to Greenlee County, which holds fewer than 10,000 people and more cattle than most cities. The size disparity matters because Arizona law applies a uniform structural template to all of them regardless.

This page covers county-level governance only. Municipal governance — cities and towns — follows a distinct legal framework addressed separately at Arizona Municipal Governance. Tribal nations within Arizona operate under sovereign authority and are not subject to county jurisdiction; that relationship is explored at Arizona Tribal Nations and State Relations. Special taxing districts, which sometimes overlay county boundaries, fall under Arizona Special Districts.

How it works

The Board of Supervisors

Every Arizona county is governed by a Board of Supervisors, composed of 3 members in smaller counties and 5 members in larger ones (Maricopa and Pima counties each have 5 supervisors, per A.R.S. § 11-401). Supervisors are elected by district to four-year staggered terms. The board functions as both a legislative body — adopting budgets and ordinances — and an administrative one, overseeing county departments and entering contracts.

The board sets the county's annual budget, which in Maricopa County for fiscal year 2024 exceeded $4.6 billion (Maricopa County FY2024 Adopted Budget). That number underscores something worth sitting with: a county board meeting in a mid-sized conference room controls resources on a scale most state agencies don't approach.

Elected Constitutional Officers

Arizona counties elect a fixed slate of officers whose authority derives directly from the state constitution or statute — not from the Board of Supervisors. These officers cannot be removed by the board, which creates a system of distributed accountability that occasionally produces friction:

  1. County Attorney — prosecutes criminal cases, advises the board, and may represent the county in civil litigation (A.R.S. § 11-532)
  2. County Sheriff — chief law enforcement officer, operates the county jail (A.R.S. § 11-441)
  3. County Assessor — determines assessed values for all taxable property (A.R.S. § 11-501)
  4. County Treasurer — collects taxes, manages county funds (A.R.S. § 11-601)
  5. County Recorder — maintains official records, administers elections (A.R.S. § 11-461)
  6. County School Superintendent — oversees fiscal and administrative functions for school districts (A.R.S. § 15-301)

The Clerk of the Superior Court, while not always categorized alongside the above, is also elected and maintains judicial records independently of the board.

The Court System Within Counties

Each county hosts a Superior Court with jurisdiction over felony criminal cases, family law, probate, and civil matters exceeding $10,000 (A.R.S. § 12-123). Justice Courts operate at the precinct level within counties, handling misdemeanors and civil claims under $10,000. Superior Court judges are appointed by the governor in counties with populations over 250,000 (Maricopa, Pima, and Pinal) under a merit-selection process; in smaller counties, judges are elected.

Common scenarios

Property tax disputes begin at the County Assessor's office, proceed to the County Board of Equalization if unresolved, and can escalate to the Arizona Tax Court, a division of the Maricopa County Superior Court with statewide jurisdiction (A.R.S. § 12-166).

Election administration illustrates the recorder-board tension in practical terms. County recorders manage voter registration and early ballots; boards of supervisors canvass results and certify elections. These are separate authorities operating on overlapping timelines under state law — a design that has generated public attention during contested election cycles in Arizona.

Land use and zoning outside incorporated municipalities falls to the Board of Supervisors, which adopts general plans and zoning ordinances for unincorporated county territory. This authority does not extend inside city or town limits.

Public health emergencies activate the county's Department of Public Health, which operates under the board but also responds to directives from the Arizona Department of Health Services. The layered authority — state mandate, county execution — defined much of the administrative dynamic during the 2020–2021 COVID-19 response.

Decision boundaries

The single most important boundary in Arizona county governance: counties can only do what the legislature expressly permits. Unlike Arizona's charter cities, which derive broad home-rule authority from Article XIII of the Arizona Constitution, counties have no inherent legislative power. A county board cannot create new taxes, establish new courts, or expand officer authority beyond what Title 11 provides.

County authority also does not extend to:

For a broader orientation to how county government fits within Arizona's full governmental architecture — state agencies, courts, the legislature — Arizona Government Authority provides structured coverage of the state's institutional landscape, including the relationships between executive departments and local entities that county residents interact with daily.

The home page of this resource connects all 15 county profiles with statewide context, allowing readers to trace how a structural rule in Title 11 plays out differently in a county of 9,000 people versus one of 4.4 million.

Understanding where county authority ends is, in practice, as useful as knowing where it begins. A county board can zone unincorporated land aggressively and still have no say over a parcel the moment a city annexes it — a dynamic that shapes development patterns across the Phoenix metropolitan area and Tucson metropolitan area continuously.

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