Legal Definitions - ad coelum et ad inferos

The Latin phrase ad coelum et ad inferos translates to "to the sky and to the depths" or "up to the sky and down to the center of the earth."

In property law, this principle traditionally describes the extent of land ownership. It suggests that a landowner not only owns the surface of their property but also the airspace directly above it and the ground directly below it, extending theoretically infinitely upwards and downwards. While a foundational concept, modern law often places practical limitations and regulations on this traditional view, especially concerning airspace (e.g., aviation) and subsurface resources (e.g., mineral rights, utility easements).

Here are some examples illustrating this concept:

• Overhanging Structures: Imagine a homeowner who discovers that their neighbor has built a new shed, and a portion of its roof or eaves extends several feet over the homeowner's property line into their backyard airspace. The homeowner could invoke the principle of ad coelum to assert their right to the airspace above their land and demand the removal of the encroaching structure, as it infringes upon their property extending "up to the sky."

• Subsurface Utility Lines: A property owner plans to dig a new well for irrigation and finds that a previous owner had granted an easement to a utility company for an underground pipeline running deep beneath their land. This situation highlights the ad inferos aspect, where rights to the subsurface are involved. While the current owner technically owns "down to the depths," the pre-existing easement grants the utility company a specific right to use that subsurface space, demonstrating how ownership below the surface can be divided or limited.

• Mineral Rights: Consider a rancher who owns a large plot of land in an area known for natural gas deposits. The rancher's ownership, according to ad coelum et ad inferos, would traditionally include the mineral rights beneath their property. This means they would have the right to extract the gas or lease those rights to an energy company, as their ownership extends "down to the center of the earth," encompassing the valuable resources found deep below the surface.