Adverse posession is a method of acquiring the title to someone else’s property by occupying the property against the rightful owner’s rights. NOTE: Adverse posession cannot occur on publicly owned (government) land.
According to Wikipedia, “Adverse possession requires the actual, visible, hostile, notorious, exclusive, and continuous possession of the property, and some jurisdictions further require the possession to be made under a claim of title or a claim of right.”
Basically, this is essentially squatting, except in the end, one can actually gain title through adverse posession. There are various requirements for gaining title, and they do vary across states. These requirements include: a) the person (adverse posessor) must pay taxes on the property for consecutive years, b) the person must use the property for an uninterrupted, continuous period of time (varies by state), c) the person must be in posession of the property openly (not hiding or secretly posessing it), d) the person must have some kind of claim for the title.
Given that the proper conditions are met for the state that the property resides in, a person can actually squat on another’s property and gain it through adverse posession.
Adverse posession has raised somewhat of a debate on owners rights, similar to eminent-domain, as both entail property owners losing out to others who wish to posess their property.