Llyn Dulyn

Llyn Dulyn (Welsh: Black lake) is a lake on the edge of the Carneddau Range of Mountains in Snowdonia. The lake covers an area of only 33 acres (130,000 m2), yet is extremely deep - it reaches to a depth of 189 feet (58 metres). Less than a kilometre to its south lies the smaller Llyn Melynllyn.

Cliffs rise steeply from the lake edge up to the summits of Garnedd Uchaf and Foel Grach, giving it a dark brooding appearance - hence its name. A number of superstitions are connected with the cwm, which has also been the site of a number of small aeroplane crashes.

The lake has a dam, originally built in 1881, to increase its water capacity, but it has been altered several times since. As a reservoir Dulyn (along with Melynllyn) provides water for the town of Llandudno. The pipes cross the River Conwy at Tal-y-Cafn bridge.

The outflow from the lake is called Afon Dulyn, and this stream also feeds water into neighbouring Llyn Eigiau. Afon Dulyn flows north-east, passing Tal-y-bont before joining the River Conwy.