It primarily regulates and legally protects real estate and is used by each state in the United States except Louisiana. It determines the liability of an owner with regards to the safety of third parties within their property.
There are three types of third person parties that are recognized by common law.
Trespasser – Someone who enters a property for personal purposes without the permission or knowledge of a landowner. The safety of adult trespassers does not fall on a landowner’s hands but it is a different story with children. Landowners have a duty to ensure the safety of children who trespass their property.
Licensee – Someone who is invited to enter and remain on a property for reasons other than commercial or business. A guest is a licensee and landowners are expected to maintain a higher level of safety for them.
Invitee – Someone who is invited to enter and remain on a property for commercial or business reasons. They are invited either implicitly or explicitly as they will benefit the property owner. Invitees receive the highest level of protection and landowners should ensure that the conditions of their property are reasonable and safe for the invitees.
Common law is different from common law property where the primary concern is the ownership of a property that was acquired during a marriage.