Caisteal Grugaig (or Dun Totaig) is an Iron Age broch near the eastern end of Loch Alsh in the Scottish Highlands (grid reference NG86682508).

The broch is located in the district of Lochalsh, and is about 9 kilometres northwest of Shiel Bridge.

[2] The interior of the broch has two intramural rooms at ground level, one of which is a small, oval cell.

[2] The other is a long mural cell, or length of ground gallery, which has a blocked doorway.

[2] In the National Museum of Scotland is a decorated steatite cup apparently from this site.