'A View of the Castle of Carlisle in Cumberland', 1773
Shows the Irish Gate and the bridge over the river Caldew. Fox may well have entered Carlisle by this route.
For an excellent range of images of this entry into Carlisle before it was demolished, see Matthew P. Emmott's The Castles, Towers, and Fortified Buildings of Cumbria, section on
'Carlisle, The Irish Gate\Caldew Gate': click on his images to enlarge them. Close that window to return.