Longest castle
Georg Reisinger
Deutschland (Burghausen)
The longest castle is the "Burg zu Burghausen" which measures 1,051.02 metres (3,448 ft 2 in) long and is located in Burghausen, Germany.

The definition of "castle" for this record is the definition of the Encyclopedia Britannica which reads "... medieval European stronghold, generally the residence of the king or lord of the territory in which it stands."