Pentland Firth

The Pentland Firth (Scottish Gaelic: An Caol Arcach, meaning the Orcadian Strait), which is actually more of a strait than a firth, separates the Orkney Islands from Caithness in the north of Scotland.

Read more about Pentland Firth:  Etymology, Geography, Crossing The Firth, Tidal Races, Tidal Power, Marine Wildlife