Chile is divided into 13 regions, each of which is headed by an intendente appointed by the President. Every region is further divided into provinces with a Gobernador Provincial, also appointed by the President. Finally each of the 51 provinces is divided into municipalities (324) which are sometimes referred to as comunas, each with its own mayor, and councilors, known as concejales elected by their inhabitants.
Each region is designated by a name and a Roman numeral, assigned from north to south. In general, the Roman numeral is used, rather than the name. The only exception is the region where Santiago is situated, which is designated RM, that stands for Región Metropolitana, Metropolitan Region.
In 2005, the Chilean congress passed a reform to create two new regions, one in the north, around the city of Arica, and one in the south centered around Valdivia (aka Region of the Rivers). Being designated by numerals XIV and XV, both break the geographical numerical order from north to south. There is speculation that the numeral system will be dropped in favor of their formal names.
The two regions, 'Arica and Parinacota' in the north (created by subdividing the Tarapacá Region), and 'Los Ríos' in the south (created by subdividing the Los Lagos Region), became operative in October 2007.
Refs.:
- http://en.wikipedia.org/wiki/Chile#Administrative_Divisions
- http://www.statoids.com/ucl.html