Prekmurje Union Day is observed in Slovenia every August 17, commemorating the reunion of the Slovene people of Prekmurje with their mother nation. This memorial day marks the inclusion of Prekmurje into the Kingdom of Serbs, Croats, and Slovenes in 1919. The region, located between the Mur River in Slovenia and the Raba Valley in Hungary, has a rich history, having been part of various states since its settlement by Slovens. After being invaded by Hungarians in the 10th century, it became part of the Kingdom of Hungary, and later the Habsburg Monarchy. Prekmurje Union Day was established in 2006, although it does not grant an additional day off for observance. The holiday celebrates the cultural heritage and traditions of the Prekmurje region.