A property tax lien is a lien or claim for money due to a federal, state, or local government for unpaid and delinquent taxes. For example, the federal government may place a lien on a homeowner’s home or other real property for unpaid federal income taxes, and state and local governments (often counties) may place a lien on real property for unpaid income or property taxes.

The federal, state, or local government entity—also known as a taxing authority—may seek to recover payment for unpaid taxes by forcing the sale of the property on which the lien is placed in the foreclosure process—a process in which the validity of the lien and satisfaction (payment) for the lien is litigated or determined in court.

In New Hampshire, a property tax lien represents a legal claim against a property by a governmental entity due to unpaid property taxes. When property taxes are not paid, the local municipality can place a lien on the property. This lien ensures that the tax authority gets first claim over other creditors in regards to the property's value. If the taxes remain unpaid, the taxing authority may initiate a tax lien sale or a tax deed sale, where the lien or the property itself is sold to collect the delinquent taxes. The process for enforcing tax liens can involve a court proceeding to confirm the validity of the lien and to order the sale of the property to satisfy the tax debt. The foreclosure process in New Hampshire allows the property owner a redemption period to pay the taxes owed plus interest before losing the property permanently. It's important for property owners to address tax liens promptly to avoid potential foreclosure and sale of their property.