The EU has fostered the development of regional thinking and regional policy through the combination of parts of existing Member-States which share common characteristics. Sometimes these regions include parts outside of official EU boundaries that can cross national boundaries.

There are two different kinds of approaches to EU regions:

Official EU Regions

This approach has been developed in the official regional policy of the European Union. Various programs have been established, all with the title of Interregio (abbreviated as Interreg).

Non-EU Regions

This approach is the result of initiatives outside of the official EU channels, including both private and local (sub-national) government initiatives. The existence of the EU and its clear support for regional programs has often inspired such initiatives. In some instances the EU stands ready to offer financial support. These initiatives are not official EU programs in the same way as the Interregio initiatives.