Fee simple is an ownership interest in real property that is the most full, unlimited, and absolute property interest recognized by law. This ownership interest of title in fee simple is also referred to as fee simple absolute; estate in fee simple; fee simple title; or simply fee, and the term is usually used to indicate the real property ownership interest a seller is transferring to a buyer.

The rights of a fee simple property owner are limited by the government’s power to tax the land (property taxes) and to purchase the land through the compulsory process mandated by state law—often as provided in the state’s constitution or in the state’s statutes—which is known as eminent domain.

In limited circumstances fee simple ownership may also be subject to the state’s police powers, the law of escheat (when the property owner dies without a will and without heirs), and encumbrances or deed restrictions on the use of the land.

In Montana (MT), fee simple ownership represents the most comprehensive type of real estate ownership. The holder of a fee simple title has the greatest extent of rights over the property, including the right to use it, sell it, lease it, or pass it on to heirs. However, these rights are subject to certain limitations imposed by law. The government retains the power to levy property taxes on the land and may also exercise eminent domain to acquire the property for public use, following the procedures outlined in the Montana Code and the state's constitution. Additionally, the state can claim ownership of the property under the law of escheat if the owner dies intestate (without a will) and without any lawful heirs. Furthermore, the use of fee simple property may be restricted by state police powers, which are laws enacted to promote public health, safety, morals, and general welfare, as well as by any encumbrances or deed restrictions that may have been placed on the property. These could include covenants, conditions, and restrictions (CC&Rs) that govern the use of the property in certain developments or neighborhoods.