The village was first mentioned in 1224 as "Gregorio (de) Haele", and means "bend of the highland".[3] Haelen developed along the Haelense Beek. It used to belong to the County of Horne, and later became part of the Prince-Bishopric of Liège. In 1679, it became an independent heerlijkheid.[4]
Aldengoor Castle was first mentioned in 1212. One tower from 15th century remains, the other three towers were destroyed during a siege in 1598 by the Dutch Republic. During the 17th and 18th century, it was enlarged with two wings. In 1903, it was used as a monastery. In 1977, a museum was housed in the castle, and it has become private property since 1996. In 2006, a bed and breakfast opened in the castle.[4][5]
The Catholic St Lambertus Church is a three aisled church built between 1953 and 1955 to replace the church which was destroyed in 1944.[4]
Haelen was home to 374 people in 1840. Until it became a part of Leudal on 1 January 2007 Haelen was a separate municipality, and included the villages of Buggenum, Horn, and Nunhem.[5]