Adverse possession—sometimes called squatter's rights—occurs when a person or entity who does not own a certain piece of real property occupies or uses it in a way that is adverse to the owner of the property—meaning the use is in conflict or at odds with the property owner’s interests.

If this adverse possession or use of the property meets the legal standard for adverse possession—often described as use that is continuous, exclusive, hostile, open, and notorious—and continues for the prescribed period of time (usually specified in the state statute)—the person or entity adversely possessing or using the property will acquire ownership of the property (title). This ownership will result in the changing of boundary lines.

Because the required adverse possession must be open, obvious, and adverse to the owner’s interests, title may only be acquired by adverse possession to the portion of property that is used in that way.

Adverse possession laws vary from state to state and may be located in a state’s court opinions (also known as common law or case law) or, more often, in its statutes.

In New Jersey, adverse possession laws allow a person to claim ownership of property not originally their own if they possess it in a manner that is continuous, exclusive, hostile, open, and notorious for a statutory period. The required period of possession in New Jersey is typically 30 years, as per N.J.S.A. 2A:14-30. However, if the adverse possessor has paid property taxes on the disputed land for a minimum of five years, the period required for adverse possession may be reduced to just five years under N.J.S.A. 2A:14-31. It's important to note that the adverse possessor must treat the property as their own, without the permission of the original owner, and the possession must be obvious to anyone, including the owner. If these conditions are met and the statutory period has passed, the adverse possessor may be able to acquire legal title to the property, potentially altering the boundary lines. An attorney can provide specific guidance and representation in matters of adverse possession in New Jersey.