Çayüstü is a village in Cide District, in Kastamonu Province, Türkiye. Çayüstü lies at 190 m above sea level, in the Küre mountains. It has 173 inhabitants. The nearest city is Bartın, 70 km to the west. Among the landmarks around are Cytorus (20 km), Carambis (25 km) and Climax (5.0 km). Among the natural features are Dağlı Kuylucu Cave (10.7 km).