Lochmaben is situated between three lochs.
The Mill Loch is the deepest of the three main lochs reaching a depth of over 14 metres (50 feet). As its name suggests it supplied a mill downstream where the old gasworks were sited on a lane named Mill Road. There was also a Lint (Flax) Mill at the head of the loch, sited on the burn coming from the Upper Loch.Its main claim to fame is that it was home to the world renowned Vendace fish the last of which was netted from the loch in 1966 and can now be viewed in the Council Chambers of Lochmaben Town Hall and in Dumfries Museum. Scottish Natural Heritage has plans to reintroduce the Vendace if the water conditions become favourable. A recent problem in the loch has been the introduction of a pernicious fringed water lily. If the lily were left to spread, 25% of the loch's surface would be covered in 10 years, changing its character completely.The loch is popular with fishermen, both local and from other parts of Scotland and Northern England. They are attracted by Coarse Fish such as Bream, Pike etc.