These cover most of South Yorkshire (including Sheffield, Barnsley, Rotherham and Mexborough), parts of north Derbyshire (including Chesterfield, Dronfield and the Hope Valley) and north-west Nottinghamshire (including Worksop), plus a small part of West Yorkshire.

[3] For 1857–1868 an S sector of the London postal district existed.

These were: The S64 district covering the Mexborough post town was originally earmarked for use as DN13, which has never been used.

S1-S14 cover the core urban area of Sheffield, with S17-S36 covering more suburban or rural areas within Sheffield's environs.

Postcodes in the range S4x relate to the Chesterfield area.