It was built as a hill castle around 1115 by Gerhard I and became the family seat of the House of Blankenheim.

With the extinction of the lines of Manderscheid-Gerolstein and Manderscheid-Kail (1742) the County of Manderscheid became the largest independent territorial lordship in the Eifel.

For a long time the castle remained uninhabited until, in 1894, Prussia started work on safety measures.

As a result, Count Dietrich III of Manderscheid-Blankenheim had a water supply tunnel excavated in 1469.

The lawyer and Catholic politician, Moritz Lieber, was born on 1 October 1790 at Blankenheim Castle.