Clan MacMillan is a Highland Scottish clan. The Clan was originally located in the Lochaber area of the Scottish Highlands during the 12th century. The clan supported Robert the Bruce during the Wars of Scottish Independence, but later supported the Lord of the Isles in opposition to the Scottish Crown. During the Jacobite rising of 1745 the clan was divided with some supporting the Jacobites and others not taking part in the rebellion.

Lochaber is a name applied to a part of the Scottish Highlands. Historically, it was a provincial lordship consisting of the parishes of Kilmallie and Kilmonivaig, as they were before being reduced in extent by the creation of Quoad Sacra parishes in the 19th century. Lochaber once extended from the Northern shore of Loch Leven, a district called Nether Lochaber, to beyond Spean Bridge and Roybridge, which area is known as Brae Lochaber or Braigh Loch Abar in Gaelic. Lochaber is now also used to refer to a much wider area, one of the 16 ward management areas of the Highland Council of Scotland and one of eight former local government districts of the two-tier Highland region. The main town of Lochaber is Fort William.