Burgruine Kaja

{{Infobox military structure

|name=Burgruine Kaja

|partof=

|location= Lower Austria, Austria

|coordinates= {{coord|48.8266|N|15.8880|E|type:landmark_region:AT|display=inline,title}}

|image= Merkersdorf - Burgruine Kaja (b).JPG

|caption= Kaja Castle near Merkersdorf in Lower Austria

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|type= Castle

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Burgruine Kaja is a castle in Lower Austria, Austria.