Assessor parcel numbers can be found on many local county property tax assessor office websites. A local taxing authority assigns APNs, typically in the city or county where the property is located.
County tax assessors assign APNs to every plot of land in a county or city. The format of the number is used to identify and track the property to assign a taxable amount to it, payable by the property owner. As of 2015, many county assessors offices have websites that allow people to search for APNs by address and displaying property information, such as lot size, property type, sales and tax history.