A squatter's right is a legal allowance to use the property of another in the absence of an attempt by the owner to force eviction. This right may eventually be converted to title to the property over time by Adverse Possession, if recognized by state law. “Squatting” is an old casual word for occupying a place that legally belongs to someone else when that owner hasn’t given permission for the occupation. “Squatter’s rights” is an assertion that someone is entitled to own land after he’s been squatting there. The legal name for squatter’s rights is “adverse possession.”
The doctrine of adverse possession discourages disuse of property. According to the doctrine, if property was abandoned, and someone else "squatted" on it for a number of years, the squatter could gain control over the land. If the squatter abandons the property for a period, or if the rightful owner effectively removes the squatter's access even temporarily during the statutory period, or gives his permission, the squatter loses the benefit of that possession. If that squatter later retakes possession of the property, that squatter must, in order to acquire title, remain on the property for a full statutory period after the date on which the squatter retook possession. However, one squatter may pass along continuous possession to another squatter, known as "tacking", until the adverse possession period is complete. In the United States, squatting laws vary from state to state and city to city.