Caithness (Scottish Gaelic: Gallaibh [ˈɡ̊al̪ˠɪv], Scots: Caitnes) is a registration county, lieutenancy area and historic local government area of Scotland.Caithness has a land boundary with the historic local government area of Sutherland and is otherwise bounded by sea. The land boundary follows a watershed and is crossed by two roads, the A9 and the A836, and one railway, the Far North Line.