PIN stands for “Property Identification Number” which is linked to ownership, ARN stands for “Assessment Roll Number” and is used for property value assessment purposes. More information can be found on the Ontario Parcel web site at: www.ontarioparcel.ca. The boundaries are often the same, but not always. For this reason, PIN and ARN are maintained in separate data bases. The images below from VuMAP show both PIN and ARN results produced from a single query location (PIN in yellow, ARN in blue).