From the Wikipedia page 
Riga Region (Latvian: Rīgas reģions), officially Riga Planning Region (Latvian: Rīgas plānošanas reģions) is one of five planning regions of Latvia, situated in the central part of Latvia, in and around the metropolis of Riga and along the shores of the Gulf of Riga. The state institution was founded on 12 October 2006, based on the creation of the region territory as prescribed by Regulations No. 133 of the Cabinet of Ministers as of 25 March 2003, the "Regulations on Territories of Planning Regions".
According to the "Law on Regional Development Riga Planning Region", Riga Region is supervised by the Ministry of Regional Development and Local Government, the decision-making authority is Riga Planning Region Development Council (RPRDC), which consists of 18 deputies appointed by the heads of the local municipalities comprising the region.
The Riga Region was created in 2006, covering the territory and using the administrative boundaries of the now defunct districts of Latvia: Limbaži, Ogre, Riga and Tukums as well as the cities of Riga and Jūrmala.