Castle of Salgó, Salgótarján, Medieval castle ruins on basalt cone near Salgótarján, Hungary.

Castle of Salgó is a medieval fortress ruin on a basalt cone near Salgótarján, situated at approximately 625 meters elevation. The remains include a square tower and fortification walls on the eastern side, where stone structures still mark the hilltop landscape.

The Kacsics clan built a square stone tower here in the 13th century, after the Mongol invasions of 1241–1242; a charter mentions Salgó Castle in 1348. Hussites held it from 1450 for ten years until King Matthias retook it, and in 1554 Kara Hamza's Ottomans took it by a ruse. Pálffy and Teuffenbach recaptured it in 1593, after which the remaining defences were destroyed.

The ruins have long inspired local identity and appear in poems and regional stories that connect the area's natural landscape with human settlement. Visitors come to experience what remains as a symbol of the region's past and its role in shaping community memory.

Marked hiking trails lead from the Salgóbánya area to the ruins, with parking available at the base of the hill. The site is freely accessible, though sturdy footwear and adequate time for the uphill walk are advisable.

The castle's name may come from the volcanic peak itself or from the tower built on it; sources do not settle which. In 1554 the garrison surrendered to Kara Hamza bey without a fight, fooled by tree trunks mounted on gun carriages that looked like cannon in the fog. The Ottomans held Salgó until 1593.