Heerlen is a city and a municipality in the southeast of the Netherlands. It is the third largest settlement proper in the province of Limburg. Measured as municipality, it is the fourth municipality in the province of Limburg.

Limburg, also known as Dutch Limburg, is the southernmost of the twelve provinces of the Netherlands. It is bordered by Gelderland to the north and by North Brabant to its west. Its long eastern boundary forms the international border with the state of North Rhine-Westphalia in Germany. To the west is the international border with the similarly named Belgian province of Limburg, part of which is delineated by the river Meuse. To the South, Limburg is bordered by the Belgian province of Liège. The Vaalserberg is on the extreme southeastern point, marking the tripoint of the Netherlands, Germany and Belgium.