The early history of Millen is closely linked with that of the Duchy of Jülich. Millen was in the Middle Ages the main glory in Selfkant. It was originally the residence of the lords of Millen, who in 1282 became part of the glory Heinsberg. Millen was elevated among the Gelderland Duke William III of Gulik, after in 1393 also became Duke of Jülich.
De Roode Beek today right along, but historically actually runs through Millen, here forms since 1815 a state border. But what seems to be a natural limit is in fact a highly unnatural rupture. On the left side of the stream, now the territory of Nieuwstadt, is namely the Castle of Millen Millen House, together with the ruins of the old medieval castle. That fortress Millen had centuries owe its existence. The village and the castle belong inseparably together and form even now together a very rustic ensemble on both sides of the stream.
But it does have a place inexorable division of property in 1815. Both typical complementary parts are now orphaned opposed.
On the right bank of the Red Brook the village can boast several other monuments. Now the castle tower is a ruin, dominates the others already ten centuries old parish church of the village. Originally an early-Romanesque hall church, dedicated to St. Nicholas, previously belonged to the castle. Rather unsightly from outside, the interior is very valuable. In addition, there are the old deanery and the tithe barn.
Also worth seeing and scenic location is the 18th-century double water (oil and flour mill) at the castle, on both sides of the Roode Beek lying, so partly in Germany and partly in the Netherlands.
Millen has been part of the Netherlands fourteen years after the Second World War, (from 1949 to 1963), as the majority of the German municipality Selfkant. The possession of this annexed by the Netherlands as a boundary adjustment area Tudderen, together with some other areas, was a symbolic compensation for the enormous suffering and damage the war had inflicted to the Netherlands.