What County Is Phoenix, AZ In?

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Phoenix, Arizona is in Maricopa County. The city is not merely inside the county — it is the county seat, which means the county courthouse, the Board of Supervisors, the Recorder’s Office and the Superior Court all sit in downtown Phoenix. Every square mile of the city of Phoenix falls within Maricopa County; unlike some Arizona municipalities, Phoenix does not spill across a county line. If you are filling in a form, filing a deed, registering to vote, or looking up property records for a Phoenix address, Maricopa County is the answer you need.

Maricopa County is the most populous county in Arizona by a wide margin, with 4,485,414 residents recorded in the 2020 Census — roughly 62 percent of the state’s entire population, and the fourth-largest county population in the United States. It covers about 9,224 square miles, which makes it larger than New Hampshire and Vermont combined. Phoenix itself accounts for about 518 square miles of that, so the city sits in one corner of a county that stretches from the Hassayampa River in the west to the Superstition Mountains in the east.

Why People Ask “What County Is Phoenix In?”

Two quirks of Arizona naming send people looking. The first is that there is no Phoenix County — Maricopa County takes its name from the Maricopa (Piipaash) people, not from its largest city, so the county name gives no hint that Phoenix is inside it. The second is that Arizona also has a town called Maricopa, about 35 miles south of Phoenix, and that town is in Pinal County, not Maricopa County. Searching “Maricopa” can therefore land you 35 miles and one county away from where you meant to be.

A third source of confusion is the metro area. “Phoenix” in casual use often means the whole Valley of the Sun, and that region does cross county lines: Casa Grande, Florence, Eloy and the town of Maricopa are in Pinal County, and Apache Junction and Queen Creek straddle the Maricopa–Pinal boundary. The city of Phoenix proper, though, is entirely Maricopa County.

Maricopa County at a Glance

Which County Is Each Phoenix-Area City In?

Most of the Valley of the Sun is Maricopa County, but the southern and eastern edges are not. Use this table to check a specific suburb.

Where Maricopa County Sits on the Arizona Map

Maricopa County occupies south-central Arizona, in the low Sonoran Desert. It borders Yavapai County to the north, Gila County to the northeast, Pinal County to the east and south, Pima County to the far south, and La Paz and Yuma counties to the west. The Salt, Gila, Verde, Agua Fria and Hassayampa rivers all converge inside it, which is precisely why the Hohokam farmed here more than a thousand years ago and why the modern city grew where it did — Phoenix is named for a city risen from the ashes of that earlier canal-building civilisation.

For the full picture, see the Maricopa County map and profile, browse all 15 Arizona counties, or look up any other place on the map of Arizona cities and towns.