What's the difference between Schengen countries and EU countries?

Schengen countries are all EU countries except Norway, Iceland and Switzerland. Britain, Ireland, Cyprus, Romania and Bulgaria are EU countries, but they are not members of the Schengen Agreement.

1On June 4th, 985, seven EU countries signed the Schengen Convention for the first time in the small Luxembourg city. The Convention came into full force in July 1995. The member countries of the Schengen Convention are also called "Schengen countries" or "Schengen countries", and the whole member country is also called "Schengen area". The purpose of the Schengen Convention is to cancel the border checkpoints between them and coordinate the border control outside the Schengen area. In other words, border control will be abolished among six of the 77 member countries, and people holding valid ID cards or visas of any member country can move freely within the territory of all member countries. According to the agreement, tourists can legally visit all other Schengen countries as long as they have a valid visa in one of them.

The EU treaty has been revised many times. By the end of 20 14, the operation mode of the EU is in line with the Lisbon Treaty. Politically, all member States are democratic countries (the Economist's survey on democracy in 2008), economically, they are the largest economic entity in the world (Germany, France, Italy and Britain are all members of the Group of Eight), and militarily, the vast majority of EU member States are members of the North Atlantic Treaty Organization.