PIN stands for Property Index Number. This unique 14-digit sequence number is assigned to the legal description for each piece of real estate in Cook County, including vacant lots, parking spaces and condominium common areas. The PIN is used for assessments, tax rate calculations and tax collections.

A PIN is to a property what a Social Security number is to a person. If you have your name placed on a tax bill for the wrong PIN and pay that wrong PIN, the taxes on the PIN you actually own are still delinquent. For that reason, the PIN is the key to making correct payments.

Match the PIN on the tax bill to the PIN on your deed. This is very important when you: (1) pay off a mortgage and take over tax payments, or (2) refinance with a new company. An attorney who handles your property matters, or in the suburbs, a township assessor, may be able to help verify a PIN. If your deed contains only a legal description, the County Clerk 's Office, which assigns PINs, can find the PIN.

Yes. When a property is divided after being altered, each new parcel gains a new legal description and, thus, a new PIN. Taxpayers should make sure they have the proper PIN when paying taxes on a new house, townhouse, loft, condo unit, and, in some cases, parking spaces.

Absolutely. You need your PIN to verify that your mortgage company is making payment on time, in full and on the right real estate. Also, if you and other owners share a PIN, as happens with newly developed property, you need to contact our Legal Department for information on submitting a payment by legal description. "Paying by Legal" helps you avoid underpaying, overpaying or having your taxes sold if others who share your PIN are delinquent.

Yes. You need the PIN to request a duplicate tax bill from the Treasurer's Office or to call with any questions you may have about payments, assessments, appeals, exemptions and tax rates.