The term "buffer zone" is often used to refer to an area between two countries, or two hostile forces within the same country. In reality, a buffer zone is not limited in its description to a land area between countries or even between forces within a country. Any area that serves to keep two areas, communities, or even populations separated may be considered a buffer zone.
In areas of the world where there has traditionally been conflict, either between warring nations or between warring factions within a nation, the term "buffer zone" has frequently been used to describe the land mass or terrain that keeps the warring parties separate. In some cases, the buffer zone may be a completely sovereign state or country. In others, it may simply be a small area of neutral territory between the parties.
The United Nations has historically declared buffer zones, or demilitarized zones, throughout the world. The Mediterranean island nation of Cyprus, for example, has been home to a United Nations declared buffer zone, or green line, that has divided the island since the Turkish invasion of the small island nation. Weapons are not allowed in the buffer zone, which is considered a de facto border between the official nation of Cyprus and the unofficial Turkish Republic of Northern Cyprus.
Although most often associated with areas of conflict, a buffer zone may also be used to describe the area surrounding a prison or other penal institution. The need to create space between incarcerated prisoners and residential or commercial areas is essential to maintain security. In the unlikely event that a prisoner escapes, the buffer zone makes it less likely that the prisoner will come into contract with innocent citizens. The uninhabited area also makes it more likely that law enforcement officials will be able to track, and ultimately re-capture the fugitive, before he or she is able to blend back into the general population.
Industrial areas, or areas where dangerous or hazardous chemicals are used or manufactured, also creates the need for a buffer zone. Often, industrial manufacturing creates toxic by-products that need to be kept clear of residential or commercial areas. In addition, some types of installations, such as a nuclear reactor, have inherent risks associated with their use and, therefore, must be kept at a safe distance from heavily-populated areas in the unlikely event of a malfunction, explosion, or other disaster.