Traditionally, the “cujus est solum ejus est usque ad coelum, et ad inferos” maxim outlined that ownership of the land extends upwards infinitely and downwards to the centre of the earth.

Today however, when an individual purchases an interest in land, they are generally entitled to the use and enjoyment of:

• the soil on and below the surface of the property;

• the air space above;

• natural products (including vegetation) attached to or growing on it;

• artificial structures or fixtures attached to it; and

• water on or under the surface, subject to the statutory schemes that regulate water ownership and use.

Further, limitations to a landholder's rights are provided within express provisions in the contract of sale, state legislation and may be specified in the original Crown grant to the land.

Although the ancient maxim allowed ownership of land to prevail downwards to the core of the earth, over time, common law decisions have altered the application of this “fanciful” principle. Significant developments limiting subsurface rights have resulted from the mining of minerals, oils and natural gases below the surface: Wandsworth Board of Works v. United Telephone Co. Ltd .

See Subsurface rights.

Height boundaries to land ownership have developed through electrical and aeronautical advancements which signalled an influx of claims in trespass. Although shifts in law have limited an individual’s airspace rights, landowners can still maintain an action in trespass if an intrusion unreasonably impedes on their enjoyment, control and use of the land. See Rights to airspace.

Land boundaries define the area to which a land holder has rights. In most states and territories, a land management authority maintains a system which specifies the legal boundaries to every registered parcel of land. Generally land boundaries can be categorised as:

• artificial or natural; or

• tidal or non-tidal.

Artificial boundaries to land remain static as they are defined by arbitrary lines which are fixed by individuals or the government. Common examples of artificial boundaries include fences, roads and buildings.

Natural boundaries are more prone to shifts due to the unpredictability of natural forces which can either erode or accrete parts of land. This can include streams, rivers and the coastline. As many Australian properties abut water, natural boundaries are further divided into tidal and non-tidal water.

All land boundaries and measurement must be determined by a registered surveyor and accepted by the state or territory land management authority before any alterations are legally recognised. Before dealing with currently registered property, an examination of original Crown grants and physical boundary evidence may be required to ascertain the existing established boundaries.

See Boundaries to land.

Accretion and erosion involve natural and physical changes to land by natural forces. Whether changes in land can be legally registered under both old system and Torrens is dependent on whether:

• natural and environmental processes were the operating cause of changes in land boundaries; and

• changes were gradual enough to be deemed imperceptible to the naked eye: Hazlett v Presnell.

See Accretion and erosion.

Encroachment issues are a central concern among landowners where individual rights may be impeded by the actions of others. Encroachment is defined in most state legislation.

The general principle is that any building that is constructed or that encroaches on the land of someone else becomes the property of that landowner, amounting to a gift. As common law attempts to achieve a just solution and apply relief to encroachment issues, disadvantages incurred by the operation of these principles can be remedied in equity and under statute. See Encroachment.