Harderwykenburg

Leer, Germany, Germany

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Harderwykenburg is one of the oldest surviving stone‑house castles in East Frisia, located in the town of Leer in Lower Saxony, Germany.

It was built shortly after the middle of the 15th century, around 1450–1480, as a compact three‑storey tower‑like stone house by the local chieftain Hayo Unken, using stones taken from a former monastery, and its thick exterior walls, up to about 1.23 meters, show its medieval defensive character.

The building later passed to the Harderwyk family through marriage and acquired the name Harderwykenburg, while its core structure and many original architectural features such as slit‑style windows have remained visible despite later alterations.

The house is now in the possession of the von Knyphausen family, is listed as a historic monument, and is mainly used as a private residence, with openings or viewings usually limited to specific public events, making it a well‑preserved but quietly integrated landmark in Leer’s old town.