View Message

My Irish surname book has it alternately spelled as MacKellow, possibly from Scots Mac Killoch ...a toponymic from Ayrshire ...

McBain's Irish translation site has the following:
ceall
g. cille, a church, so Irish, Early Irish cell; from Latin cella, a cell, a hermit's cell especially, whence the Gadelic use. Hence cealloir, superior of a cell, and the name Mackellar. "A retired spot"

Best I can do ...