Glaslyn (Welsh: Blue lake) is a lake in the Snowdonia National Park in Gwynedd, north-west Wales.It is found at approximately 600 metres (2,000 ft) above sea level in a cwm on the eastern flanks of Snowdon. It is a rough ellipse in shape, about 500 metres (1,600 ft) east–west and about 300 metres (980 ft) north–south, and the Miners' Track runs along the northern shore.