The NW (North Western) postcode area, also known as the London NW postcode area, is a group of postcode districts covering part of northwest London, England. It is the successor of the NW sector, originally created as part of the London postal district in 1856.
The London postal arrangements were refined in 1917 when the sub-districts (as appended to postal addresses) were given new alpha-numeric identities for public use; the districts usually cover a wider area than their names might suggest. The district names are no longer included in the postal address because the first part of the postcode contains equivalent sorting information.
Within each NW postcode district, PO boxes are allocated to a unique postcode sector, except for two districts which use all available sectors for ordinary addresses and therefore have their separate non-geographic districts: NW1W for PO boxes in NW1 and NW26 for PO boxes in NW10.
List of postcode districts
The approximate coverage of the postcode districts, with the historic postal district names shown in italics: