LEITH. " The surname of Leitli is of great antiquity in Scotland, and those who bore it held, in a remote era, vast possessions, including the barony of Eestalrig, and others in the shire of Mid-Lothian, and territory of Leith, whence, it is presumed, the name was taken." B.L.G. The pedigree is traced only to the year 1350. The baronet's family descend from William Leith, who was provost of Aberdeen in 1350. According to Douglas there were at the latter end of the last century six distinct families of Leith, all of whom could trace their origin to that personage. Courthope's Debrett.

Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.