Origins of the name CULPIN or CULPAN
Finding the original derivation of any surname is not an exact science but this has been particularly difficult with this name. There has been much speculation that the origins were French and certainly that seems to be the best gues we can make at the moment. The CULPIN version is a current surname in France, Belgium and parts of German near the French border, but there is a similar name COLPIN which when pronounced even today sounds very much like our names CULPIN and CULPAN.

Phillipe Catelin, a french genealogist places the origins in a diminutive of the christian name Nicholas (often termed COL)

Nom assez fréquent dans le Nord-Pas-de-Calais et en Belgique. C'est un diminutif du nom de baptême Nicolas, formé à la fois par aphérèse (Nicolas, Nicol > Col) et par suffixation (suffixe diminutif -epin).

Jan George's book on Culpans also traces back the origins of the Culpan form of the surname to France but with a different origin.

The name Culpan is not a common one and is known only in the Halifax area of West Yorkshire from earliest times. It is peculiar to that part of the ancient parish of Halifax allotted to William of Warren, by the King, and comes from the Old French word "culpan" or "colpan" meaning "a detached part".