Boldogkő Castle, Medieval castle ruins in Boldogkőváralja, Hungary.

Boldogkő Castle is a stone fortress standing on a 245-meter-high hill, featuring remaining walls, towers, and wooden walkways along the ridge. The site includes several sections connected by paths and platforms that offer different views across the surrounding landscape.

The earliest part, a keep ringed by a defensive work, was probably built after the Mongol invasion, either by Tyba, son of Jaak of the Tomaj clan, or by Aba Amadé. A charter of around 1295 records the castle as "Castrum Boldua", exchanged by Tyba with King Andrew III. After the Aba family's defeat the castle passed to the Drugeths, who likely added the palace wing and the prismatic tower.

The castle's name, Boldogkő, means "happy stone" in Hungarian. The site is a stop on the Országos Kéktúra, the national Blue Trail long-distance hiking route. Inside the restored exhibition rooms, visitors can see the castle's 16th-century smelting furnace, which was used to produce bronze for counterfeiting coins.

A wooden bridge provides access to the castle, and visitors can explore both the lower and upper sections of the site. A medieval-style restaurant on the grounds offers refreshments during your visit.

The castle's 16th-century furnace, used to produce bronze for counterfeiting coins, is a rare industrial monument. Restored exhibition spaces display it today. The wooden walkway along the rock ridge leads to a small open shelter with a peaked roof, and the village and fields lie below.