Velešín, Castle ruin in Sedlce, Czech Republic.

Velešín is a castle ruin on elevated ground near Sedlce with remaining stone walls from the 13th century displaying Romanesque construction methods. The site preserves sections of defensive fortifications and gateway foundations that reveal medieval building techniques.

Founded by a Přemyslid ruler in the first third of the 13th century, Velešín was first mentioned in 1266 when Přemysl Otakar II gave it to the noble Čéč of Budějovice. The Rosenbergs bought it in 1387 and held it until 1487, when Vok of Rosenberg ordered it abandoned; by 1541 it was described as deserted.

The site received designation as a cultural monument of the Czech Republic, marking its role in preserving medieval architectural heritage.

The ruin lies in the water-protection zone of the Římov reservoir but is freely open. A branch off the blue-marked hiking trail from Sedlce leads to the remains; there is no car park or organised access at the site. The core sits on a narrow rock ridge, with the rear part about ten metres lower.

The castle core was ringed by a parkán, a narrow outer ward, and at its head stood a massive round bergfrit with an internal diameter of 3.7 m. Its ground floor held a recess with a latrine shaft more than two metres deep, and the tower was deliberately demolished when the castle was abandoned.