The area Retford is situated in was on the border of the territories of the Brigantes and the Corieltauvi during the Iron Age period. It is likely that the existence of Retford is partly owed to its water resources, in the form of both the river Idle (and its crossing) and the wells that are dotted around the area that are either still in existence or can be identified from placename evidence. These include Spa Common, Cobwell Road (named after the Cob Well) and the ancient well at Welham (called 'Wellun' in the Domesday Book).