Burg Linau, Medieval castle ruin in Linau, Herzogtum Lauenburg, Germany.

Burg Linau is a ruined motte-and-bailey castle whose remains lie on three low hilltops in a row in Linau, Herzogtum Lauenburg. The surviving foundation walls of the bergfried are over two metres thick, built of unhewn fieldstones bound with Segeberg limestone. The castle site measured about 500 by 100 metres, and a section of the moat, once linked to the Bille, is still visible.

Linau was first mentioned in 1230, and at the end of the 13th century the robber barons von Scharpenberg built the fortified castle here. In 1291 the Wendish princes and cities and the dukes of Lauenburg allied against them, and the Peace of Deitzow required the Scharpenbergs to raze the castle themselves; they rebuilt it, and in 1308 the Lübeck chronicler Detmar records it as restored. In 1349 a coalition including Holstein counts, Lauenburg and the cities of Lübeck and Hamburg besieged it for three weeks; the Scharpenbergs surrendered on 23 September 1349, and 1,500 men demolished the walls and tower.

The name Linau was first recorded in 1230, before the Scharpenbergs built their castle at the end of the 13th century. The site is a motte-and-bailey type, a tower mound castle, of which most noble castles of the 11th to 15th centuries in Schleswig-Holstein were built of wood on earthen mounds. Visitors can still see a section of the moat, which was connected to the Bille, the river that rises nearby.

You can reach the ruins via walking paths that also lead to the nearby Billequelle spring and the surrounding landscape. It is advisable to wear sturdy footwear since the terrain is rough and uneven in places.

The tower foundations, uncovered and renovated in 2018, contained a later brick kiln built into the masonry. The castle site itself spans roughly 500 by 100 metres, and a surviving stretch of the moat once connected with the Bille, which rises nearby.