Every piece of land in Arizona has exactly one Assessor’s Parcel Number — the permanent ID that ties together its permits, deeds, ownership, and sales history. Here’s how to read one, how each county formats them, and four ways to find the APN for any property.
What an APN actually is
An APN — Assessor’s Parcel Number, sometimes called a parcel number, parcel ID, or tax parcel — is the unique identifier a county assessor assigns to a single parcel of land for property-tax purposes. Every parcel has exactly one, and it does not change when the property sells, gets re-addressed, or is re-zoned. That permanence is the point: the APN is how a building permit, a deed, the owner of record, and the sales history all tie back to the same piece of land.
The number encodes a location in the assessor’s map system. In Maricopa County, for example, the first three digits are the map book, the next two are the page within that book, and the final digits identify the parcel on that page — so neighboring parcels usually share their leading digits.
An APN is not an address
A single parcel can carry many street addresses — a strip mall, an apartment complex, a corner lot with entrances on two streets — and addresses change when streets are renamed or units re-numbered. The APN stays fixed through all of it.
That is exactly why serious property data is keyed on the APN rather than the address. When PlumbIntel fuses a building permit with the parcel’s owner of record and its last sale, the join runs on the normalized APN — a permit written “301-45-678” and an assessor record written “30145678” resolve to the same parcel. Address-keyed joins silently miss; APN-keyed joins don’t.
How Arizona counties format APNs
Each Arizona county runs its own assessor map system, so the digit pattern varies. The dashes are cosmetic — assessors and title companies drop them freely, which is why any system joining on APNs must normalize them first.
Maricopa County (Phoenix metro)
Eight digits in a book-map-parcel pattern, written ###-##-### — for example 301-45-678: map book 301, page 45, parcel 678. Some parcels carry a trailing letter (301-45-678A) after a split.
Pima County (Tucson metro)
Book-map-parcel with a longer parcel segment, commonly written ###-##-#### (nine digits) or ###-##-###X with a letter suffix — for example 304-74-2220. The leading three digits are still the assessor book.
Other counties (Pinal, Yavapai, Coconino, Yuma…)
The same book-page-parcel idea with county-specific digit counts and suffix conventions. When in doubt, search the address on the county assessor’s site — every Arizona county assessor publishes a free parcel lookup — or use the free address search below, which shows the APN on the property record.
Four ways to find a property’s APN
1. A property-tax statement or deed
The APN is printed on every county property-tax bill and on the recorded deed — usually near the top, labeled “Parcel Number,” “APN,” or “Tax Parcel.” If you own the property, this is the fastest offline route.
2. The county assessor’s website
Every Arizona county assessor runs a free parcel search by address or owner name. Maricopa’s and Pima’s are the busiest; both return the APN, the owner of record, and the assessed values.
3. A title company or escrow file
If a transaction is in flight, the preliminary title report lists the APN on page one — title plants are keyed on it.
4. Search the address on PlumbIntel (free)
Search any Arizona address and the property record shows the APN alongside the permit history for that parcel — every permit pulled at that address, who pulled it, and what it was for. No signup required.
Why APNs matter for permits and construction
Building permits are filed against an address, but the property they attach to is a parcel. When a contractor, supplier, or investor wants the full story on a property — what work has been permitted there, who owns it, when it last sold — the APN is the thread that connects county permit records, assessor rolls, and recorded sales.
PlumbIntel normalizes APNs across every jurisdiction it ingests and joins them county-scoped (a Maricopa APN never matches a Pima parcel, even when the digits collide), which is how a permit search resolves to owner names and sales history rather than a bare permit list.
Look up any Arizona address
See the APN, owner of record, and full permit history for any property — free, no signup.
Frequently asked questions
What does APN stand for?+
Assessor’s Parcel Number — the unique ID a county assessor assigns to one parcel of land for property-tax purposes. Also called a parcel number, parcel ID, or tax parcel number.
How do I find a property’s APN in Arizona?+
Four ways: read it off a property-tax statement or deed; search the address on the county assessor’s website; check a preliminary title report; or search the address on PlumbIntel — the APN appears on the property record, free.
Is an APN the same as an address?+
No. The APN is a permanent parcel ID. One parcel can have several addresses, and addresses can change — the APN stays the same, which is why property records key on it.
What does the Maricopa County APN format mean?+
Eight digits as book-page-parcel (###-##-###): the assessor map book, the page within it, then the parcel on that page. A trailing letter (e.g. 301-45-678A) marks a parcel split.
Do APN formats differ between Arizona counties?+
Yes. Every county uses the book-page-parcel idea, but digit counts differ — Maricopa uses 8 digits (###-##-###), Pima commonly 9 (###-##-####), and other counties have their own patterns, sometimes with letter suffixes.
Do the dashes in an APN matter?+
No — they’re cosmetic. “301-45-678” and “30145678” are the same APN. Any system matching APNs must strip separators first, which is exactly what PlumbIntel does before joining permits to parcels.
Can two properties share an APN?+
No — one parcel, one APN. But one parcel can hold many units or addresses (an apartment complex is often a single APN), and a subdivided parcel gets new APNs for the pieces.
Does the APN change when a property is sold?+
No. Sales, re-addressing, and re-zoning don’t change the APN. It changes only when the parcel itself changes shape — a split or a merge — and then the county assigns new numbers.
Can I look up permits by APN?+
Yes — because permits, ownership, and sales all join on the parcel, searching a property on PlumbIntel shows its APN together with every permit on record at that parcel.
Chris Brannan· Founder, Plumb Intelligence
Founder of Plumb Intelligence. Building the honest layer over Arizona’s public construction records — permits, parcels, licenses, and sales, fused and measured daily from Gilbert, AZ.
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