Groenlo is a city in the municipality of Oost Gelre, situated in the eastern part of the Netherlands, on the German border, within a region in the province of Gelderland called the Achterhoek. Groenlo was a municipality until 1 January 2005, when it merged with Lichtenvoorde. Until 19 May 2006 Groenlo was the official name of Oost Gelre. As of 1 January 2006 Groenlo, including its hamlet Zwolle, counted a population of 10,067. Groenlo is known locally and historically as Grolle, Groll or Grol.
Today, Groenlo is known primarily for its beer brewery Grolsch, which was in business since 1615, but has been closed in 2004 when it moved to Boekelo. Grolsch produces many specialty beers and its beer is exported all over the world. Groenlo's military history is less well known today.