An uncommon name:
Clemitson is an uncommon surname.
Within the UK, practically all the present day Clemitsons are related in some way.
Back to Northumberland:
As well as the UK, branches of the family are to be found in Canada, South Africa, and Australia.
Nearly all are descended from branches of the Clemitson family who lived in the Allendale & Hexham area in Northumberland in the 17th Century.