The Schengen Area is an area comprising 26 European countries that have officially abolished all passport and all other types of border control at their mutual borders. The area mostly functions as a single jurisdiction for international travel purposes, with a common visa policy. The area is named after the 1985 Schengen Agreement signed in Schengen, Luxembourg.
Of the 27 EU member states, 22 participate in the Schengen Area. Of the five EU members that are not part of the Schengen Area, four—Bulgaria, Croatia, Cyprus, and Romania—are legally obliged to join the area in the future, while the other one—Ireland—maintains an opt-out. The four European Free Trade Association (EFTA) member states, Iceland, Liechtenstein, Norway, and Switzerland, are not members of the EU, but have signed agreements in association with the Schengen Agreement. Three European microstates that are not members of the European Union but which are enclaves or semi-enclave within an EU member state—Monaco, San Marino, and Vatican City—are de facto part of the Schengen Area.