From "The Surnames of Scotland" by Dr. G.F. Black
Kincaid, Kinkaid is a place name in the Parish of Campsie, Stirlingshire.
Robert de Kyncade was a witness 1450.
Patrick and George de Kyncad were witnesses in Edinburgh 1457.
David de Kyncade was baillie of Edinburgh 1467 and 1493.
Thomas de Kyncayd was a witness in Biggar 1545, and spelt it Thomas Kyncaide in 1550.
James and Alexander Kincaid in Kilchoan 1609.
Kinkaid 1547, Kyncaid 1510, Kynked 1493.