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 Delaware, a property tax lien is a legal claim against a property for unpaid property taxes. This lien has priority over most other liens or claims on the property, including mortgages. When property taxes are delinquent, the county in which the property is located may place a tax lien on the property. If the taxes remain unpaid, the county can initiate a tax sale process, where the property may be sold at a public auction to satisfy the tax debt. The process for enforcing tax liens, including notification, redemption periods, and the conduct of tax sales, is governed by Delaware state statutes, specifically Title 9 of the Delaware Code. Additionally, for federal tax liens resulting from unpaid federal income taxes, the Internal Revenue Service (IRS) can place a lien on all of a taxpayer's property, including real estate, personal property, and financial assets. The federal tax lien process is governed by federal law, primarily under the Internal Revenue Code. Foreclosure of a tax lien in Delaware typically involves a judicial process where the validity and satisfaction of the lien are determined in court.