Line in column on Northern or Eastern city (7)
I believe the answer is:
lincoln
'eastern city' is the definition.
'line in column on northern' is the wordplay.
'line' becomes 'l'.
'column' becomes 'col'.
'on' is a charade indicator (letters next to each other).
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'l'+'in'+'col'+'n'='LINCOLN'
'or' is the link.
(Other definitions for lincoln that I've seen before include "memorial site for ..." , "16th US president" , "Eastern county town" , "Former US president" , "An assassinated US president" .)