North Humberside

It was introduced by the Royal Mail on 1 July 1974, when some addresses were altered in response to the changes in administration brought about under the Local Government Act 1972.

All of the post towns included in the North Humberside had formerly been part of the Yorkshire postal county.

A changeover period of one year was allowed by the postal authorities, with the new county compulsory from 1 July 1975.

Coincidentally, Humberside was abolished for local government purposes in the same year, with the area north of the Humber becoming two unitary authority areas: East Riding of Yorkshire and Kingston-upon-Hull.

Although counties are no longer used for sorting mail, under the Royal Mail's flexible addressing policy users can choose to add a county to an address as long as the post town and postcode are included.