Burg Hermülheim, Medieval castle in Hürth, Germany.

Burg Hermülheim was a medieval fortress in Hürth that featured water-based defenses and strategic positioning. The castle stood at a key point along Roman water supply routes and incorporated protective structures designed to guard against attack.

Rizo de Mulenheim, a ministerialis of the Archbishop of Cologne, was documented in 1166. In 1256 the Teutonic Order acquired the lordship and castle from Dietrich von Richzemulenheim in exchange for a farm at Erp. After 1762, commander Ignaz Felix von Roll had the building rebuilt as a three-storey manor house for the Koblenz bailiwick's summer residence.

The Teutonic Order acquired the estate in 1256 and renamed the settlement Herrenmülheim, from which Hermülheim derives. The castle served as the seat of the Koblenz bailiwick, and its commanders, including Ignaz Felix von Roll, resided there and at nearby Brühl Palace. After 1762 it was rebuilt as a summer residence for the order's commanders.

Only a protected gateway arch remains from the original castle today, standing in central Hürth, as the main complex was demolished in 1964. The gateway is easily accessible and represents the final vestige of this former fortress.

The fortress was completely destroyed in 1964 during a planned fire brigade training exercise. Firefighters deliberately set the building ablaze to practice their extinguishing and rescue techniques.