Last to finish by river (6)
I believe the answer is:
endure
'last' is the definition.
(I know that last can be written as endure)
'finish by river' is the wordplay.
'finish' becomes 'end' (come to an end).
'by' says to put letters next to each other.
'river' becomes 'ure' (river in Yorkshire).
'end'+'ure'='ENDURE'
'to' is the link.
(Other definitions for endure that I've seen before include "Put up with something" , "Suffer, tolerate" , "Last or suffer patiently" , "Go through" , "Tolerate, put up with" .)