Location and coordinates are for the approximate centre of Llandecwyn within this administrative area. Geographic features and populated places may cross administrative borders.
Gazetteer of the British Isles (Edinburgh: Bartholomew, 1887). John Bartholomew
Llandecwyn, par. and vil., Merioneth, in NW. of co., 4 m. NE. of Harlech, 6915 ac. (180 water), pop. 381.