Several surnames derived from placenames not found in Cornwall have either become numerous here or largely confined to Cornwall over the centuries. These have to all intents and purposes become Cornish surnames. some, such as Chesterfield or Kendal, may have origins many hundreds of miles away, but the largest number, as we might expect, originated in Devonshire.
We can take all the surnames listed in The Surnames of Cornwall where I identified an origin in a Devonian placename which did not also occur in Cornwall and map them in the mid-1600s. We get the following distribution.
Most of the surnames from Devonian places stayed close to the Tamar, but occasional examples cropped up quite early in the west. The presence of both Seccombe and Lamerton on the Lizard in the 1500s might suggest sea-borne migration along the coast, as does the map above, where districts on the south coast seem to have a higher number of such surnames.
While some of these placenames only appeared in Cornwall at a later date some were already present by 1500. Lobb is an example of a surname that was established quite far west by the 1500s.
Cornish studies resources 
Bernard, Do you have any insight as to why people migrated into Cornwall? My own surname study shows only very local movement for most of the period up to about 1700. Thanks for the blog. John Beckerleg
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It’s a good question, John. From surname studies we know that in-migration was not that high in terms of the total frequency. On the other hand, the presence of surnames with external origins indicates that it was not unknown. A lot of this – at least from Devon and maybe other parts of south-west England – resulted from the usual short-distance ‘churning’ that demographers have long recognised for the medieval and early modern periods as people moved from parish to parish for work.
What’s more difficult to explain are the long-distance movements. I guess a lot of this would be connected to trading links, some to higher level job movements as clerks for example got bureaucratic posts for Cornish landlords or the Duchy, or clergymen after the Reformation when they could legally marry. Some may have resulted from movements of the military, particularly the Navy, some just to vagrancy. But each move would have had its own discrete history and reasons. In the 1400s many Bretons migrated into Cornwall for work – as servants and craftsmen, these presumably being better paid than in Brittany. The same thing may have applied to movement from some regions in the British Isles.
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The surname Gwennap and its variants would fall into this category, would it not?
What about the surname Carbis? Thank you for keeping Cornwall in close to me. Pat Guynup Corbus
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Not really Pat. Gwennap was a saint’s name in Cornwall while Carbis comes from the Cornish word for a causeway. Both originated in Cornwall.
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Bernard would you have any insights regarding my Cornish family’s surnames of Gummoe and Truscott. My father emigrated to Canada with his parents and two sisters in 1925 from the village of St. Ewe.
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Yes, Gummow ’emerged in the St Austell district in the 1500s’, probably from places in St Austell or Probus (my book p.73) ansd Truscott is ‘said to have its source in the place of the same name (menaing beyond the wood in Cornish) at St Stephen by Launceston’, although I am sceptical given its early geography (see p.177)
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