The surname Muir originally denoted someone who lived beside a moor and is derived from the Scots form of middle English “more”.
The clan is said to have come from Ireland and would soon settle at lands in the Scottish Lowlands, particularly at East Ayrshire. The historic seat of the clan was at Rowallan Castle, which stands on the banks of Carmel Water, north of Kilmarnock.
Today, the clan is armigerous – meaning it has no current clan chief.