Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.
LOUDON
As described in historical dictionaries
Patronymica Britannica (1860)
LOUDON. Loudoun, a great parish in Ayrshire. The progenitor of the family was James the son of Lambin, who obtained "Laudon," from llichard Morville, who died in 1189, the minister of William the Lion.
Surname type: Location or geographical feature
Origin: Celtic
Region of origin: British Isles
Country of origin: Scotland
Religion of origin: Christian
Language of origin: Gaelic