KML is from Wikidata The S postcode area, also known as the Sheffield postcode area, is a group of postcode districts in England, which are subdivisions of eight post towns. 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.