Kallmuth Castle, Medieval castle in Mechernich, Germany.

Kallmuth Castle is a two-storey rubble-stone building beside the tower of St. George's Church in Kallmuth, part of Mechernich. Its former gable roof has been replaced by a lean-to roof, and a round-arched entrance on the west side leads to the first residential floor. Quarter-circle sandstone corbels once supported the wooden beam ceilings; the upper room is cut down in height by the lean-to roof. The economic buildings were rebuilt in the 19th and 20th centuries, and the former castle buildings now house a modern residential complex.

A knight of Kallmuth is documented in 1285, suggesting the castle was built in the 13th century. The von Friemersdorf genannt Pützfeld family held it until 1749, by then likely leasing it out. In 1770 it was split between Hilger Dahmen and Freiherr von Gymnich, whose share passed to Graf Ambrosius von Spee in 1780. After 1908 it belonged partly to the Schmitz family until 1989, and it is now a residential complex.

The name Kallmuth comes from the knightly family von Kallmuth, first recorded in 1285 with a knight of that name; the line ended in 1515 with Johann von Kaelmoutten. From 1749 the castle was held by owners living elsewhere, in Kirspenich, and was probably leased out. Since the agricultural use ended, the former castle buildings have been converted into a modern residential complex.

The castle buildings now house a modern residential complex and are not open as a museum; visits are limited to the exterior. The complex stands directly beside the tower of St. Georg's church, and the two-storey rubble-stone building shows a round-arched entrance on its west side. The site is on uneven ground, so wear sturdy shoes.

The castle stands right beside the tower of St. Georg's church, and its two-storey rubble-stone building once had a pitched roof, later replaced by a lean-to roof that cut down the height of the upper room. Quarter-circle sandstone corbels that once carried the wooden ceilings can still be seen. Since 18 July 1989 it has been listed as monument No. 71 in Mechernich.