Which European country is divided into areas called Cantons

Switzerland
A canton is a type of administrative division of a country.

In general, cantons are relatively small in terms of area and population when compared to other administrative divisions such as counties, departments or provinces. Internationally the best-known cantons, and the most politically important, are those of Switzerland.

As the constituents of the Swiss Confederation, theoretically (and historically) the Swiss cantons are semi-sovereign states.

The term is derived from the French word canton meaning corner or district (from which "Cantonment" is also derived).

Read more...https://en.wikipedia.org/wiki/Canton_(country_subdivision)