Which legal concept allows a party to exercise ownership rights without the landowner's permission?

The concept that allows a party to exercise ownership rights without the landowner's permission is adverse possession. This legal principle enables a person to claim ownership of land under certain conditions, despite not having the owner's consent. Typically, for a successful adverse possession claim, the claimant must demonstrate that their use of the property has been continuous, open, exclusive, and hostile to the interests of the true owner for a statutory period, which varies by jurisdiction.

In contrast, an easement is a legal right to use another person's land for a specific purpose, but it does require some form of permission or agreement, making it fundamentally different from adverse possession. Termination generally refers to the ending of a legal agreement or the cessation of a right. Merger, in legal terms, typically involves the combination of two properties or rights into one, which does not pertain to claiming ownership rights without consent. Thus, the unique nature of adverse possession—as it enables a claimant to obtain legal title to land they do not own—clarifies why it is the correct choice in this scenario.