Arthur, William (1857) An Etymological Dictionary of Family and Christian Names. New York: Sheldon, Blakeman. Public Domain.
CORNISH
As described in historical dictionaries
An Etymological Dictionary of Family and Christian Names (1857)
(origin: Local) Belonging to Cornwall, indicating the place from which the family came.
Patronymica Britannica (1860)
CORNISH. Belonging to Cornwall— applied originall}' to one who had removed from that to another county. A family so called at St. Issey in Cornwall, "originally descended from one William Cornish, who settled here temp. Queen Mary, a Welshman.''' D. Gilbert's Cornw., ii. 255.
Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.
Surname type: Location or geographical feature
Origin: English
Region of origin: British Isles
Country of origin: England
Religion of origin: Christian
Language of origin: English