A prescriptive easement—also known as an easement by prescription or an adverse easement—is an easement (right to use property) created by a use of property (the servient estate) that is open, continuous, and adverse to the owner of the property (the servient estate).

To satisfy the requirement that the use be continuous, the use must take place over a required period of time—which may be specified in a state’s court opinions (common law or case law) or in its statutes if the state legislature has written the law regarding easements into statutes or code. If the state legislature has written a law in statutes or codes the law is said to be codified.

In Alaska, a prescriptive easement is established when an individual uses another's property in a manner that is open, notorious, continuous, and adverse to the interests of the property owner for a statutory period. The required period of continuous use in Alaska is 10 years, as specified in Alaska Statute 09.45.052. This means that if someone uses a portion of another's land without permission, in a way that a reasonable property owner would notice, for at least 10 years, they may be able to claim a legal right to continue that use. It is important to note that the use must not be secretive, must be without the landowner's permission, and must be uninterrupted for the entire statutory period. If these conditions are met, the user may file a lawsuit to have the prescriptive easement recognized by the court. Property owners who wish to prevent prescriptive easements should take steps to interrupt any adverse use of their land before the statutory period elapses.