Adverse possession is a legal tool through which a person or organization gains title to land by, essentially, squatting on that land.
The elements of adverse possession are slightly different in each state, but most states require that the squatter’s use be (1) actual (2) open & notorious (3) continuous (4) hostile and (5) exclusive (6) for a period of years (also known in legalese as the “statute of limitations”).
Actual: The squatter has to actually use the land in a way that a true owner of land would use it; his use has to be consistent with the character of the land.
Open & notorious: The squatter can’t hide his use of the land; the legal owner should be able to tell easily that the squatter is using the land, if the owner inspects the property.
Continuous: The squatter can’t abandon the property once he’s begun to squat there without restarting the clock.
Hostile: The squatter cannot have permission from the owner to qualify under adverse possession. If the owner has given the squatter permission to use the property, there isn’t really any squatting going on at all. Therefore, if a person grows on a vacant lot for years with permission from the owner, that person cannot gain title through adverse possession.
Exclusive: The squatter must, essentially, treat the property as if it were his own and use it as a legal owner would, to the exclusion of others.
Statute of limitations: In Maryland, like in most states, the statute of limitations is 20 years.
In Texas, however, the statute of limitations for adverse possession is quite short: 5 years. A few citizens of Texas have attempted to use the short adverse possession statute to their advantage by squatting in foreclosed houses.
Here’s a link to a local news story on a hopeful adverse possessor of a foreclosed home in Texas: Adverse Possession in Texas.
Some garden groups in the US have obtained title to abandoned urban lots through adverse possession, especially when the land owner on record is dead and his/her heirs don’t care about the lot. As an example, a pro bono attorney in Philadelphia helped a youth organization obtain title to land they had used as community gardens since the 1940s!