County Donegal, Ireland is all exposed ground, Atlantic light, and routes that feel tied to the land beneath them. Climb toward Errigal or Muckish for stark quartzite views, walk the Lough Veagh Trail to Glenveagh Castle, or follow the Sliabh Liag Cliff Top Path above the ocean. From Glengesh to Inishowen Head and Arranmore, Donegal hiking stays rugged, spacious, and unmistakably coastal.