Adverse possession combines the abstract idea of rights in land with the real fact of occupation on the ground in a manner that is inconsistent with the rights of the true owner. An owner who neglects to exercise his rights of ownership and possession over all his land may lose his right by the adverse possession of another. A trespasser who occupies or squats on land may gain title to it if certain conditions have been met.

The conditions which must be fulfilled to perfect a possessory claim to land are actual, open, visable, notorious, exclusive and continuous possession and enjoyment of the land in a fashion which is adverse to the title of the owner. The onus is on the claimant to prove valid possession of the property by meeting all the above conditions, that is, reliance is placed on the strength of the claim, not the weakness of the owner's possession. Against the Crown, the period is 40 years.

Definition of Conditions:

1. Actual Possession - The land must have been actually used by the claimants without the approval of the owner. The use must be consistent with the nature of the land and in a manner similar to the use a true owner might make of the land. Isolated and separate acts of tresspass do not establish possessory title.
2. Open and Notorious - The use and occupation must take place in an open and visible manner so that others, in particular the true owner, might know of or could regularly observe it. The use and occupation will generally be widely known by others in the area. The degree of notoriety will be consistent with the nature of the area in which the land is located.
3. Continuous - The possession must be continuous for the duration of the statutory period (i.e., daily, weekly, depending on the nature and location of the land). A series of adverse possessors may be linked together to make a continuous period, if previous trespassers followed each other in close succession in an unbroken chain.
4. Exclusive - The possession must be exclusive, not only with regard to the true owner, but also all others. Random acts of possession by various individuals will not meet the exclusive requirement for a possessory claim.

There are several mechanisms for an adverse possessor to perfect their claim, including actions under the Quieting Titles Act, or a claim pursuant to s.37 of the Crown Lands Act.