What an APN is
The APN is the county's primary key for a parcel. Some states call it a parcel ID, PIN, AIN, or strap number. They all do the same job. The county assessor assigns it, the recorder uses it on the deed, and the tax collector uses it on the bill.
An APN follows a structure that the county chooses. A common pattern in California is book, page, and parcel: 1234-567-890. Cook County, Illinois uses a 14 digit PIN. Florida often uses folio numbers. The format is local; the function is the same.
Three ways to look up an APN
- Search by address. Open Landy's APN lookup or your county GIS site and search the street address. The parcel polygon and APN load together.
- Tap the map. Pan to the lot you care about and tap it. The parcel card opens with the APN, acreage, and owner where the county publishes it.
- Search by owner. Most county sites support owner name search. Useful when you do not have a clean address, such as undeveloped land.
Reading what the digits mean
In states that use book, page, and parcel, the first block tells the assessor which book a parcel was originally drawn into. The second block is the page within that book. The third block is the parcel on that page. Two lots with the same first two blocks are usually neighbors.
In states that use a single long PIN, segments encode township, section, and a sequential number. The pattern is consistent inside a county and changes between counties.
Verify before you act
- Cross check the APN against the most recent tax bill on the county site.
- Confirm the owner name on the parcel card matches the deed.
- If a parcel was split or merged recently, expect the APN to change.
Key takeaways
- The APN is the county's parcel ID. Find it by address, by map, or by owner.
- The digits often encode book, page, and parcel, or township and section.
- Verify against the latest tax bill and deed before you rely on the number.