The Schengen Area is a zone comprising 26 European countries that have abolished internal borders and established a common external border. The area is named after the Schengen Agreement, signed in the small town of Schengen in Luxembourg in 1985. The Schengen Area is one of the largest free-travel zones in the world and covers an area of 4.5 million square kilometers.

The 26 Schengen countries are: Austria, Belgium, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, and Switzerland.

The Schengen Area allows for free movement of people within its borders, meaning that citizens of Schengen countries can travel freely without border checks or passport controls. Additionally, non-Schengen citizens who have been granted a Schengen visa can also travel freely within the Schengen Area during the period of their visa.

However, while there are no internal border controls within the Schengen Area, there are external border controls at the external borders of the area. This means that travelers entering the Schengen Area from outside must go through passport and security checks at the border.

The Schengen Agreement also established a common set of rules for visas, asylum procedures, and police cooperation. For example, the Schengen Information System (SIS) is a central database used by Schengen countries to exchange information on persons and goods that may pose a security threat.

Overall, the Schengen Area is an important aspect of European integration, promoting freedom of movement and cooperation among its member countries.