The SM postcode area, also known as the Sutton postcode area,[2][3] is a group of seven postcode districts in England which are subdivisions of five post towns. These postcode districts cover part of south-west London, as well as a small part of north Surrey.
The main sorting office is in Sutton, with outgoing mail being sorted at Croydon Mail Centre, and the area served includes most of the London Borough of Sutton, while most of SM4 covers the southwestern part of the London Borough of Merton and most of SM7 and a small part of SM2 cover the northern part of the borough of Reigate and Banstead in Surrey. SM2 also covers the village of East Ewell in the borough of Epsom and Ewell.