Šumburk, Medieval castle ruin near Šumná, Czech Republic

Šumburk, also called Nový Šumburk or Neuschönburg, is a ruined Gothic castle on the summit of Šumná hill at about 540 metres, three kilometres west of Klášterec nad Ohří in the Ore Mountains foothills. Substantial parts of the outer walls, the palace and the great residential tower survive, the tower standing to the fourth floor with walls 1.7 metres thick.

Vilém of Šumburk founded the castle after dividing the Perštejn estate with his cousin Aleš on 26 October 1431, and by 1435 he styled himself as seated at Nový Šumburk. The Fictum family later repaired it, but a fire before 1559 left it unmaintained, and it became a ruin during the 17th century.

The castle's documented names are Šumburk and Nový Šumburk, German Schönburg and Neuschönburg; Mercator's 1585 map of Saxony marks hill and castle as "Neu Schonberg". The hill itself is called Šumná, a name also used for the village that stood by the farm below until 1945.

The ruin lies on the summit of Šumná, about three kilometres west of Klášterec nad Ohří, and is reached on foot; the approach climbs the southern slope past the remains of two gateways. A baroque farmyard ruin stands at the foot of the hill. The tower survives to the fourth floor, so the masonry is uneven underfoot.

The ruins show clearly different sections of masonry side by side, each reflecting a different owner who modified the castle before the fire ended its story. Reading these differences in stone is a way of tracing ownership changes without any written guide.