Dereköy is a village in Erfelek District, in Sinop Province, Türkiye. Dereköy lies at 155 m above sea level, in the Küre mountains. It has 292 inhabitants. The nearest city is Sinop, 29 km to the east. Beaches nearby: Harzana (10 km). Among the landmarks around are Erfelek Dam (6.6 km) and Alaaddin Mosque (29 km). Among the natural features are Tatlıca Waterfalls (9.3 km).