APN Lookup: How to Find an Assessor's Parcel Number for Any Property
An APN is the number an assessor assigns to one parcel. How to do an APN lookup, with formats for Maricopa, Cook, NYC, Harris, Philadelphia and Florida.
Quick answer
An APN lookup finds the assessor's parcel number, the unique ID a county assigns to one parcel of land. You can find it on a tax bill, a deed or an assessment notice, or by searching the county assessor's site by address or owner name. The format differs by county.
What is an APN (assessor's parcel number)?
APN stands for assessor's parcel number. The Maricopa County Assessor describes it this way: "Each parcel is given a unique number to identify it" (Maricopa County Assessor, FAQ). The number belongs to the land, not to a person. When the owner changes, the number stays.
That is why every property record system keys off it. Assessments, tax bills, exemptions and often recorded documents all point back to the same number. If you can find the right parcel number, every other search about that property gets easier.
The name changes by place. Arizona says APN. Cook County, Illinois says PIN (property index number). New York City uses borough, block and lot. Harris County, Texas uses an account number, and Philadelphia uses an OPA account number. They all do the same job: identify one parcel.
Definition
APN (assessor's parcel number) — A unique number a county assessor assigns to one parcel of land so the parcel can be found, valued and taxed. Different places call it a parcel number, parcel ID, PIN or account number.
What does a parcel number look like in each county?
There is no national format. Each county designs its own, so a number that is valid in one county can mean nothing in the next. The table lists what the official pages we read say for the places HeritageDeed covers.
| County | What it is called | What the official page says | Where to look it up |
|---|---|---|---|
| Maricopa County, AZ | APN (parcel number) | Three to four parts: Assessor book number (3 digits), map number (2 digits), item number (3 digits), plus an optional letter if the parcel was split. | Maricopa County Assessor parcel search |
| Cook County, IL | PIN (Property Index Number) | 14 digits, assigned to the legal description of each piece of real estate, including vacant lots and condominium common areas. | Cook County Assessor PIN search; Cook County Treasurer |
| New York City, NY | BBL (borough, block, lot) | Identifies a tax lot by borough, block and lot. See our BBL guide. | NYC property records, ACRIS |
| Harris County, TX | Account number | The Tax Office lets you search by account number, property address or owner. | HCAD property search; Harris County Tax Office |
| Philadelphia, PA | OPA account number | The Office of Property Assessment tells residents to search by address or OPA account number. | property.phila.gov |
| Hillsborough County, FL | Folio and parcel number | The Property Appraiser's search offers separate Folio and Parcel Number fields. | Hillsborough County Property Appraiser |
How do I look up an APN or parcel number?
Check a document you already have
The fastest APN lookup is a piece of paper. Maricopa County says the number "is listed on your Notice of Value." Cook County says the 14-digit PIN is printed on your tax bill, your closing documents and deed, and notices from the Assessor. Check those first.
Use the county assessor or appraisal district search
Go to the assessor's site (or the appraisal district in Texas, or the property appraiser in Florida) and search by street address. Maricopa's parcel search accepts a parcel number with no dashes, a street address or the exact owner name as recorded. When you search by address, pick the parcel number that appears in the results.
Search the treasurer or tax collector with the number
Once you have the number, the same ID works on the tax side. Maricopa says to type your APN into the Treasurer's website to see the tax bill. Harris County's Tax Office lets you search by account number, address or owner.
Match the number to the legal description
An address can point to the wrong parcel, especially for condos, split lots and vacant land. Compare the parcel number, the owner name and the legal description on the assessor page against the vesting deed before you rely on the result.
Record the number with the date you looked
Parcels get split, combined and renumbered. Write down the number, the county and the date, so you can explain a mismatch later.
How does a Maricopa County APN work?
A Maricopa APN is built from three parts that narrow the location step by step. The Assessor's page explains that the first three digits are the book number, which covers large parts of the county; the next two digits are the map number, which is the map within the book; and the last three digits are the item number that identifies the specific property. When a parcel has been split, a letter after the last three digits shows which part it is.
Format is forgiving. The Assessor says "any format works": a number typed as 111-11-111-A, 11111111 or 11111111a will all find the parcel. Those are the Assessor's own placeholder examples, not real parcels.
Scale explains why the number matters. On 2026-10-03, the Maricopa County Assessor's GIS parcel layer returned a count of 1,760,690 parcels when queried for its total (Maricopa County Assessor GIS, parcel count query). With that many parcels in one county, a street address alone is a weak identifier, and the APN is the unambiguous one. The count is a snapshot of the layer on that day and changes as parcels are split or combined. For lien and recorded-document checks in that county, see Maricopa County lien search and our Maricopa County title search page.
What is a Cook County PIN?
A Cook County PIN is a 14-digit number. The Cook County Treasurer says it is "assigned to the legal description for each piece of real estate in Cook County, including vacant lots, parking spaces and condominium common areas," and that it is used for assessments, tax rate calculations and tax collections (Cook County Treasurer, About Your PIN).
The Treasurer compares a PIN to a Social Security number for a property, and gives the practical reason: if you pay the wrong PIN, the taxes on the PIN you actually own are still delinquent. It advises matching the PIN on the tax bill to the PIN on your deed, especially after paying off a mortgage or refinancing.
The Assessor's office says the 14-digit PIN appears on the tax bill, the closing documents and deed, and Assessor notices (Cook County Assessor, Where do I find my PIN?). Its site also has a search by address if you do not know the PIN. For recorded documents against a PIN, see Cook County deed search and the Cook County title search page.
How do NYC, Harris County, Philadelphia and Florida identify parcels?
New York City does not use a single run-together number in everyday searches. A parcel is a tax lot identified by borough, block and lot, written together as a BBL. Our guide, what is a BBL, covers how to read one, and how to read ACRIS shows how recorded documents are tied to it.
In Harris County, Texas, the Tax Office's payment page says you can search for a property "using account number, property address or property owner" (Harris County Tax Office, Property Tax). The county appraisal district (HCAD) assigns the account. HCAD's own search page blocked our automated fetch, so we have not described its digit format here. Check the account number on your tax statement. The Harris County title search page covers records there.
In Philadelphia, the Office of Property Assessment tells residents to visit property.phila.gov "to search for your address or OPA account number" (City of Philadelphia, Office of Property Assessment). That portal also shows ownership, sales history, value and physical characteristics. See the Philadelphia deed search guide and the Philadelphia title search page.
Florida has no one format because each county's property appraiser runs its own system. Hillsborough County's search page, for example, has separate "Folio" and "Parcel Number" fields (Hillsborough County Property Appraiser). The Florida Department of Revenue says statewide parcel data can be viewed and downloaded from the Florida Geographic Information Office Open Data Portal, and that parcel-level shapefiles are published on its Map Data directory (Florida Department of Revenue, Assessment Roll and GIS Data). Our Hillsborough County title search page covers that county's records.
What an APN lookup does not tell you
What can I do once I have the parcel number?
With the number you can run a tax check, pull the assessed value and read the legal description. Our property tax records lookup guide walks through where each county posts tax data, and delinquent property taxes explains what unpaid bills turn into.
You can also use it to answer who owns the parcel. The assessor's owner field is a starting point, and how to find out who owns a property explains how to confirm it against the deed. For a plain-language view of the lot itself, a plat map shows how parcels are drawn.
HeritageDeed runs county records searches in the counties listed on title search: Current Owner Search $49, Two Owner Search $79 and 30-Year Search $129. A records search reports what is recorded. It is not title insurance and not legal advice.
Key takeaways
Key takeaways
- An APN is the county assessor's unique ID for one parcel. It stays with the land when the owner changes.
- The name and format are local: APN in Maricopa, a 14-digit PIN in Cook County, borough-block-lot in NYC, an account number in Harris County, an OPA account number in Philadelphia.
- Find it on a tax bill, deed or assessment notice first, then on the assessor or appraiser's search by address.
- Maricopa's GIS parcel layer returned 1,760,690 parcels on 2026-10-03, which is why an address alone is a weak identifier.
- Match the number to the deed and legal description. An APN lookup does not show liens, and it is not a title search.
Frequently asked questions
- What is an APN number?
- An APN, or assessor's parcel number, is a unique number a county assessor gives to one parcel of land. Maricopa County says each parcel gets a unique number to identify it. The number is used for valuation and tax bills and stays with the land when ownership changes.
- How do I do an APN lookup by address?
- Open the county assessor's or appraiser's property search and enter the street address. Select the matching result and read the parcel number on the property page. In Maricopa County, search by street number, direction and street name without the street type, then pick the parcel number shown.
- Where can I find my parcel number without searching online?
- Look at your property tax bill, your deed or closing documents, and your assessment notice. Cook County says its 14-digit PIN is printed on all of these. Maricopa County says the APN is listed on the Notice of Value the Assessor mails.
- Is a parcel number the same as a PIN, folio or account number?
- They serve the same purpose but are not interchangeable. Cook County calls it a PIN, Harris County and Philadelphia use account numbers, and Hillsborough County lists both a folio and a parcel number. Always use the number with the county that issued it.
- Can I find the owner with an APN lookup?
- Often yes. Assessor pages usually list an owner name, and Maricopa also searches by owner name. But the assessor's name can trail a recent deed. To confirm ownership, compare it with the recorded deed at the county recorder or clerk.
- Does an APN lookup show liens or mortgages?
- No. The assessor's record is built for valuation and taxes, not for recorded claims. Liens, mortgages and easements are in the county recording office. A search of those records reports what is recorded, and it is not title insurance or legal advice.
- Why does the same property have more than one parcel number?
- A parcel can be split or combined, and the number may change. Maricopa County adds a letter after the last three digits when a parcel has been split. Condominium units and common areas can also have their own numbers, as Cook County notes for common areas.
- Is an APN lookup free?
- Searching the assessor's or appraiser's website for a parcel number is a public service on the pages we read, and we saw no fee listed. Fees can apply to bulk data or certified copies, so check the specific office's page before you request those.
Sources
Primary records and official documentation cited in this article.
- 1Maricopa County Assessor, Frequently Asked Questions
- 2Maricopa County Assessor GIS, Parcels layer count query
- 3Cook County Treasurer, About Your Property Index Number (PIN)
- 4Cook County Assessor, Where do I find my PIN?
- 5Harris County Tax Office, Property Tax payment options
- 6City of Philadelphia, Office of Property Assessment
- 7Hillsborough County Property Appraiser, Home
- 8Florida Department of Revenue, Request Assessment Roll and GIS Data
HeritageDeed provides public-record search reports only. Reports do not constitute title insurance, an attorney opinion of title, or a title insurance commitment.