
Various forms of this name are all in current use in Galloway, but the name goes back to a Gaelic spelling: Mac Shitrig (son of Sitric). Black lists several findings of this name from the 14th Century forward: John MKethirryke as a tenant in villa de Prestoun in 1376; Thomas Makettrik and his heirs having a charter of the lands of Kelauch in Galloway in 1476; and John McQuhitrig witnessing a charter of amortization by the rector of Newlands in 1504.
It is the latter connection which could be the best link to the Maxwells, for it may have meant Newlaw, a Maxwell property. The nearest place name spelled Newlands is actually far from Galloway, near Hermitage Castle in Armstrong County.
Black also tells us that some with this name changed it to Ketteridge, a change deemed more genteel.