Prácheň, Medieval castle ruin in Velké Hydčice, Czech Republic.

Prácheň is a ruined Gothic castle on a ridge above the right bank of the Otava at about 505 m, 1.5 km southwest of Horažďovice. Its three-part layout had a round bergfrit behind which a long courtyard was flanked by palace wings; parts of the round tower, the eastern wall with four bastions and rubble mounds of the other walls survive.

The castle was built in 1315 by Bavor III from Strakonice, replacing an earlier Přemyslid hillfort that served as a regional administrative center. This transition marked a shift toward new fortification techniques and strengthened control over the territory.

The castle gave its name to the Prácheň region, and the hillfort was recorded in 1045 as the centre of the Prachin district. The village below the castle vanished during the Hussite wars; only the church of St Kliment survived, next to today's cemetery.

The ruins remain accessible throughout the year and are located in an area with hiking paths connecting nearby Horažďovice and the Otava valley. The hilltop location makes navigation and exploration straightforward.

The castle gave its name to the whole Prácheň Region, and the office of castellan is documented here in 1184 with Vítek I of Prčice, ancestor of the Vítkovci. The site was abandoned by the mid-16th century and is recorded as deserted in 1558.