CR postcode area

The CR postcode area, also known as the Croydon postcode area, is a group of eight postcode districts in England, within ten post towns. These cover parts of southern Greater London and north-east Surrey.

The main sorting office is in Croydon, and the area served includes most of the London Borough of Croydon, the southeastern part of the London Borough of Merton and small parts of the London Boroughs of Sutton and Bromley. Most of CR3 and CR6 cover the northern part of the Tandridge district of Surrey, and the southern part of CR5 covers a small part of the borough of Reigate and Banstead.

Croydon was the second town, after Norwich, to have experimental postcodes, introduced in 1966. This trialled the postcode area CRO (letter 'O'), while Norwich used NOR for its equivalent. It was decided that the outward (first) part of a postcode should be alphanumerical, so CRO became CR0 (with a zero) and NOR became NR1. The CR1 postcode has not been introduced, making CR the only postcode area with a district 0 but not a district 1.

Originally there were only the districts CR0, CR2, CR3 and CR4 - in the 1990s CR5 was split from CR2, CR6 and CR8 were split from CR3, and CR7 from CR4.

The CR0 postcode district covers the largest population in the UK.