Groenlo is a city in the municipality of Oost Gelre, situated in the eastern part of the Netherlands on the German border, a region in the province of Gelderland called the Achterhoek. Groenlo was a municipality until January 1, 2005, when it merged with Lichtenvoorde. Until May 19 2006 Groenlo was the official name of Oost Gelre. As of the first of January 2006 Groenlo, including its hamlet Zwolle. Groenlo is known locally and historically as Grolle, Groll or Grol.