The Kasselburg is a ruined hill castle on a 490-metre-high basalt massif in Pelm near Gerolstein in the county of Vulkaneifel in the German state of Rhineland-Palatinate.

Hitherto it had been assumed that the lords of Blankenheim had built it shortly after 1335, but structural investigations have shown that the tower underwent several phases of construction and cannot just be the work of one architect.

It is from that period that the large outer bailey, with its burgmann houses and domestic buildings, dates.

Many interest groups have claimed the Kasselburg for themselves throughout history, so that in 1674 the Imperial Chamber Court of Wetzlar was called upon to put an end to the property disputes.

This marked the beginning of the decline of the castle: in the 18th century it was still temporarily the seat of an Arenberg forester, but by 1744 it was described as dilapidated.