The Schengen area is made of 25 European countries. Some countries are part of the European Union, but do not belong to the Schengen area. These are the United Kingdom and Ireland. Other countries, like Norway and Iceland, are not part of the European Union, but are part of the Schengen area following a cooperation agreement signed with the Schengen States.
In addition, with regards to France and the Netherlands, the Schengen regulations only apply to their European territories. The Principality of Monaco allows entry on its territory without any formality to Schengen visa holders..
The Schengen area is an area of free movement of persons. In accordance with the Schengen Convention of 14 June 1985, the 25 States, which are members thereof, have abolished checks on persons at the time of crossing of their internal borders. Hence the checks on persons are only carried out at the time of crossing of the external border of a member State, which then acts on behalf of all of the other States of the Schengen area.
The Republic of Cyprus is in the process of finalising the criteria required for a Schengen entry and it is anticipated that the Republic will be joining the European border-free zone in 2014.