Pajrek, Castle ruin in Nýrsko, Czech Republic

Pajrek is a castle ruin on a rocky spur of Hraničář mountain at 617 m, about 1.25 km south of Nýrsko. Its core is a massive donjon measuring roughly 16 × 16 m, one of the largest towers in the Czech Republic, with its north side built into the perimeter wall.

The Lords of Janovice built the castle in the first half of the 14th century; it is first documented in 1360. Bavarian troops captured and burned it in 1472, and by 1504 it was recorded as deserted. Jindřich Kostomlatský of Vřesovice bought it in 1512 and partly restored it, but after his execution in 1520 it decayed; a 1556 description calls it deserted.

The castle's name comes from the German Baiereck, meaning a castle built against the Bavarians at the border. In 1412 Jan of Janovice let servants of Jindřich of Rožmberk live at Pajrek while Jindřich supplied food and drink for the whole castle. The ruin has been a protected cultural monument since 1964.

The ruins can be reached from Nýrsko by following marked hiking trails that climb steeply to the elevated location. Sturdy footwear and some effort are needed to reach the site.

The castle's massive residential tower, about 16 by 16 metres, is among the largest of its kind in Bohemia. Rubble from the collapsed tower was later used to build the farmstead below the ruins.