Harasov Castle, Medieval castle ruin in Bosyně, Czech Republic.

Harasov Castle is a medieval ruin located within the Kokořínsko reserve, where sandstone rocks and marshlands frame the remnants of the former structure. The site sits near the Pšovka river valley, making it part of a geologically distinctive landscape.

The Hrzán family built the castle, probably Dobeš of Újezd, who took the predicate "of Harasov" in 1420 after fighting against the Hussites and receiving estates from Emperor Sigismund. The deserted castle passed with the Chodeč estate to Václav Šťastný Pětipeský in 1604 and thus to the Byšice domain.

The name Harasov comes from the Hrzán family, whose member Dobeš of Újezd adopted it in his title in 1420; the ruin was also called Krvomlýn. The rock-cut cellars, the only surviving part, were later used by millers from the nearby Nový mlýn on the Vrutický potok, who carved out more in the mid-19th century and later converted them into a recreational rock dwelling still in use.

Visitors approach the ruins by following marked hiking trails beginning at the Harasov reservoir dam in the Mělník District, marked with yellow or red blazes. The paths cross varied terrain, so proper footwear and attention to the route are advisable.

The cellars cut into the rock are the only part of the castle that survives; millers from the nearby Nový mlýn on the Vrutický potok stream used them and carved further chambers in the mid-19th century, erasing the original layout. They were later adapted into a rock dwelling still used for recreation.