Kyšperk, Gothic castle ruin in Krupka, Czech Republic

Kyšperk is a castle ruin perched on a hilltop with stone walls and towers rising above the Ore Mountains and surrounding valleys. The structure displays Gothic defensive architecture with multiple wall rings and fortified towers.

The castle was probably founded at the start of the 14th century by King John of Luxembourg or by Ota of Bergov, who received it as a fief; it is first mentioned in 1319. In 1334 Bishop Jan of Dražice bought it, and Jan of Jenštejn later added a chapel and a large residential tower. Hussites took it by 1433, and after a fire in 1526 it was abandoned.

The castle gave its name to the Kyšperští z Vřesovic branch, founded by Jaroš, son of the Hussite captain Jakoubek z Vřesovic. The German name Geiersberg, or Supí hora, survives in the name of the hill spur above Unčín where the ruins stand.

Access to the ruin has been prohibited since late June 2024, so the site cannot be entered. The remains stand on a spur of Supí hora above Unčín, in the Teplice district, at about 450 m elevation; the former Dresden–Teplice postal road once passed directly by the castle.

A round tower stood apart from the castle, separated from it by a wide moat; only low terrain traces of the square gate tower survive. On 10 September 1806, after the Battle of Kulm, Russian grenadiers hid in the ruins and fired on a retreating French column crossing the Geiersberg pass.