The Castle of Melgaço is a well-preserved medieval fortification at the heart of the town, its keep and curtain walls dating from the 12th and 13th centuries. The castle occupies the high ground of the old town, and from the ramparts you can see north into Galicia and south towards the mountains of Peneda-Gerês.
The interior is open to visitors and houses a small exhibition on the castle's military history and the medieval town. The defensive position is impressive — the walls are thick and the tower gives a clear view over the Minho valley and the Spanish border a few kilometres away. The old quarter around the castle has granite houses and a network of narrow lanes that are pleasant to walk.