The assessor's parcel number is a number assigned to individual property lots by a city or county property tax assessor. City or county assessors collect information from deeds, property titles and other recorded documents and draw up parcel maps showing property lots within given municipality or county boundaries, according to the Nevada County Assessor.
Locate the assessor's parcel number on your property tax bill. Most APNs contain three sets of numbers—indicating book number, page number and lot number—separated by dashes and beginning with APN.
Check with your city or county assessor's office to find your assessor's parcel number. Many county governments offer online links or tools to county assessor resources; check your local government's website to connect to the property tax assessor's office, or check state government resources for county listings. California, for example, provides links to all county assessor offices through its government portal (see link in References). If online resources are not available, assessor's parcel numbers and their related maps are public information, so you should be able to make an appointment to view the assessor's maps for your area at the assessor's office.
Find your APN by contacting the real estate agent you used to buy your house. Realtors have access to the assessor's parcel maps through the systems they use to list properties for sale, according to the Humboldt County Association of Realtors. If you do not have an established relationship with a particular Realtor in your area, contact one of the nearby real estate agencies and ask if it would perform a simple search in the listings system to locate your APN.