By public domain (also called demanio) is understood the set of assets") and rights of public ownership destined for public use (such as public roads and paths), or for a public service (such as a public hospital, a public school, the offices of a City Council or any other facility) or those that a law qualifies as public (such as beaches, waters or mines "Mina (mining)")) and whose private use requires an administrative concession or a permit that only the administration public can grant.

Certain legal systems consider that the public domain is made up of those assets whose owner is a community. In this sense, communities of irrigators, pastures, forests, etc., would be examples of public domain.

Public domain should not be confused with that which has no owner. The latter is called res nullius and can be appropriated by anyone.

According to the Water Law, the public hydraulic domain (DPH) includes, among other assets, the channels of natural, continuous or discontinuous currents and the beds of lakes and lagoons and those of surface reservoirs in public channels.