Llyn Cwm Bychan
{{Use dmy dates|date=November 2019}}
{{Infobox body of water
| name = Llyn Cwm Bychan
| image = Llyn Cwm Bychan.jpg
| caption = A narrow road leads to the single farm at the head of the valley.
| image_bathymetry =
| caption_bathymetry =
|pushpin_map=Wales Gwynedd
| location = Gwynedd, North Wales
| coords = {{coord|52|51.7|N|4|1.6|W|region:GB_type:waterbody|display=inline,title}}
| lake_type = natural
| inflow =
| outflow = River Artro
| catchment =
| basin_countries = Wales
| length =
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| elevation = {{convert|180|m|abbr=on}}
| frozen =
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}}
Llyn Cwm Bychan is a lake in north Wales, and is one of the sources of the River Artro which flows south westwards through Llanbedr and onwards to the sea.
It is located in the Rhinogydd mountains of Snowdonia.
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