Douglas (Dubh Glas) ...

... is Gaelic for black water owing to peat in the stream.
Apparently the first village to be named Douglas lies a couple of miles off the M74 in south Lanarkshire, a peaty stream flows through it.
The Douglas family lived in various castles in the area and in more recent times a mansion near the village.
The mansion was demolished in 1930s and all that remains is this gatehouse which can be seen at Happendon Services.
It is said that there are 56 towns and villages called Douglas world wide - and it all started here.