Llyn Conwy is the primary source of the enigmatic river discharging into the Irish Sea between the medieval walled fortress town of Conwy and the ancient copper mines of the Great Orme... the ethereal upland lake (1,488ft) the temporary repository of the input of numerous small streams draining the Migneint boglands north of Penmachno. Great Bronze Age cairns crown the skyline peaks of Arenig Fach (Carnedd y Bachgen) and Arenig Fawr (Moel yr Eglwys) to the south-east, rising above what is surely one of North Wales' most inhospitable landscapes when the not infrequent mists/rains sweep in.
The immediate environment of Llyn Conwy is endowed with several cairns of its own, two of which are cited by a local estate representative and the Gwynedd Archaeological Trust (PRN 6047) as being of probable prehistoric origin [Latham, J., 1988, Ysbytty Estate; Smith,G., 2002, Prehistoric Funerary and Ritual Monuments: West Conwy / North Gwynedd]. To my mind such provenance would not be surprising at the birthplace of a mighty river.
The cairn at SH77544579 is well placed upon Bryn Owen overlooking the south-western corner of the lake. Another is given at SH78554614 near the eastern shore.... however I assumed this to refer to the cairn upon the small island just within the lake at this point.... whether they are one and the same I therefore unfortunately cannot confirm.
Incidentaly GAT also mention a 'possible' prehistoric ring at SH77864713, that is a little below the summit of Pen y Bedw to the north:
'U-shaped wall of piled stones just below the summit of Pen y Bedw. May be a prehistoric stone circle, such as a kerb cairn'. [Source: Smith,G., 2002, Prehistoric Funerary and Ritual Monuments: West Conwy/North Gwynedd]
Archaeology aside, a visit to Llyn Conwy should, in my opinion, feature upon the itinerary of any traveller interested in the sacred landscapes of North Wales. River sources always have that 'special atmosphere' which mere words can never define. The lake would appear to be most easily approached via Llyn Cottage on B4407 (never tried this route), that is just east of the Pont ar Gonwy, where the fledgling river begins to gather form for the journey ahead. However I would recommend taking the public footpath leaving the (very) minor road near Haodfyredwydd to the west. It is possible to park a car a little south (uphill) of the latter. For awareness please note that this road, a favourite shortcut of locals, can be very intimidating / dangerous in poor conditions, the ground falling away very sharply to the floor of Cwm Hafodyredwydd below. I managed to just evade slithering over the edge one icy winter..... so please stay safe.