From the longer Wikipedia page [1]

There are five planning regions of Latvia (Latvian: Latvijas plānošanas reģioni); Kurzeme, Latgale, Riga, Vidzeme and Zemgale. The boundaries of the regions aligns to the boundaries of the municipalities of Latvia following the municipality reform of 1 July 2009. The planning regions of Latvia are not administrative territorial divisions, since they are not mentioned in the law that prescribes the administrative territorial divisions of Latvia.

Regional institutions began formation 1997 according to municipal initiatives on the planning of common development. Following legislation on regional development, the five planning regions were created according to the 5 May 2009 decision no. 391 of the Latvian Cabinet of Ministers: "Decisions on Territories of the Planning Regions.