Harlech is a town and seaside resort in North Wales, lying on Tremadog Bay, and within the Snowdonia National Park. It has a population of 1,264, of whom 63% speak Welsh..
The town is best known for Harlech Castle, begun in 1283 by Edward I of England, captured by Owain Glyndŵr, and later the stronghold of Henry Tudor. The castle was originally built next to the sea, but geological processes have changed the shape of the coastline, and the castle now lies on a cliff face, about half a mile inland. The town has since developed with housing estates on the flat low town area and hillside properties in the high town around the shopping street, church and castle. The two areas are linked by a steep and winding road called Twtil.
Other attractions in Harlech include its beach backed with sand dunes and the famous Royal St David's Golf Club. The Rhinogydd or Rhinogs range of mountains lies to the east. The town is in the traditional county of Merionethshire.
The town has a railway station served by the Cambrian Line.
The song Men of Harlech is associated with the town.