The freshwater islands in Scotland include those within freshwater lochs and rivers – including tidal areas, so the islands may not always be surrounded by freshwater. It has been estimated that there are at least 31,460 freshwater lochs in Scotland and that 1.9 per cent of the land surface is covered by freshwater. The distribution has a north-west to south-east gradient, with the highest concentrations occurring on the islands of the Outer Hebrides.
The more notable freshwater islands include Lochindorb Castle Island, Loch Leven Castle Island, St Serf's Inch and Inchmahome, each of which have had a role to play in Scottish history. Inchmurrin, the largest freshwater island in the British Isles, is in Loch Lomond, which contains thirty or more other islands.
Various names are used repeatedly. "Inch" or Innis is a Scots word that can mean 'island' (although it is also used for terra firma surrounded by marsh). Similarly, Eilean is the Gaelic for 'island'. A common suffix for offshore islands in the north of Scotland is "-holm", derived from the Old Norse holmr, meaning a 'small and rounded islet'. This list excludes artificial crannógs and the numerous small freshwater islands with no recorded name.