r From Gateshead to Darlington(which is a newcastle following town, I live there) used to be County Durham. Majority of our fan base outside Sunderland are in county durham, Gateshead is split more in Newcastle's favour but they now run into each other only separated by bridges. North of the tyne is pure newcastle following and the bulk of the area's population, add 300-400k if it suits you.
