A military base is a facility directly owned and operated by or for the military or one of its branches that shelters military equipment and personnel, and facilitates training and operations. A military base always provides accommodations for one or more units, but it may also be used as a command center, training ground or proving ground. In most cases, military bases rely on outside help to operate. However, certain complex bases are able to endure on their own for long periods because they are able to provide food, water and other necessities for their inhabitants while under siege. Bases for military aviation are called military air bases, or simply "air bases". Bases for military ships are called naval bases. Jurisdictional definition Military bases within the United States are considered federal property and are subject to federal law. Civilians (such as family members of military officers) living on military bases are generally subject to the civil and criminal laws of the states where the bases are located. Military bases can range from small outposts to military cities containing up to 100,000 people. A military base may belong to a different nation or state than the territory surrounding it. Naming The name used generally refers to the type of military activity that takes place at the base, as well as the traditional nomenclature used by a branch of service. A military base may go by any of a number of names, such as the following: Ammunition dump Armory Arsenal Barracks Cantonment Casern Combat outpost (COP) DoDAAC Facility Fire support base (FSB, FB) Forward Operating Base (FOB) Fortification Garrison Installation Joint base Magazine Main Operating Base (MOB) Marine Corps base Military airbase, airfield or field Military camp Naval air station Naval base Naval dockyard Observation post Outpost (OP) Presidio Proving ground Reservation Shipyard or yard Station Types of establishment Depending on the context, the term 'military base' may refer to any establishment (usually permanent) that houses a nation's armed forces, or even organized paramilitary forces such as the Police, Constabulary, Militia, or Guards. Alternatively, the term may refer solely to an establishment which is used only by an army (or possibly other land fighting related forces, such as marines) to the exclusion of a base used by either an air force or a navy. This is consistent with the different meanings of the word 'military'. Some examples of permanent military bases used