SW1A postcode district

Postcodes and sectors

145 of the district's 355 postcodes are live in the ONS Postcode Directory of August 2026. A postcode directory says whether a code is in use, never who is there. The live postcodes centre on 51.50455, -0.13223, which locates the district, not a building.

Companies registered in SW1A

Companies House lists 1,276 companies with a registered office in SW1A; 656 of them at addresses shared by 25 or more companies (1 October 2026 snapshot). 25 is the count at which the address lookup reports a company cluster.

Places OS Open Names lists for SW1A

• Greater London
• London
• City of Westminster
• Wandsworth

Roads filed under SW1A

Named roads first, then numbered ones. A road is filed under one district even where it runs through several, so a street missing here may be listed under a neighbouring district — which is why the address lookup never calls a British street absent. Great Britain has no open register of buildings, so a listed road never means a building on it exists.

• Arlington Street
• Bennet Street
• Blue Ball Yard
• Bridge Street
• Canon Row
• Catherine Wheel Yard
• Cleveland Row
• Craig's Court
• Derby Gate
• Downing Street
• Great Scotland Yard
• Horse Guards Avenue
• Horse Guards Road
• King Charles Street
• Little St James's Street
• Marlborough Road
• Park Place
• Parliament Street
• Queen's Walk
• Richmond Terrace
• Russell Court
• Scotland Place
• Spring Gardens
• Stable Yard
• Stable Yard Road
• St James's Place
• St James's Street
• Treasury Passage
• Tyburn Quay
• Westminster Bridge Road
• Whitehall
• Whitehall Court
• Whitehall Gardens
• Whitehall Place

Check an address in SW1A

Check an address in SW1A

The same road list through the API, from the outward code alone:

curl "https://spaw.co/api/v1/address/streets?country=GB&postal_code=SW1A" \
  -H "Authorization: Bearer $SPAW_KEY"

Common questions about SW1A

What does an SW1A postcode tell you?

That the address lies in the SW1A district of the SW (South West London) postcode area, and the place OS Open Names most often lists first for its postcodes is City of Westminster. The district alone does not place a street: the inward half of the full postcode narrows the address to one of the district's 145 live postcodes.

Where the counts come from

• ons-postcode-directory · version 2026-08 · Contains ONS, OS and Royal Mail data © Crown copyright and database right 2026, Open Government Licence v3.0. Northern Ireland postcodes are excluded: their reuse needs a Land & Property Services licence.
• os-open-names · version 2026-11-01 · Contains OS data © Crown copyright and database right 2026, Open Government Licence v3.0.
• uk-companies-house · version 2026-10-01 · Companies House free company data product, Open Government Licence v3.0

What each figure means, and what a district page never says, is set out in Reading a British postcode district page; the glossary defines a postcode district, a postcode area, a postcode directory and a street register.

Data synced on 2026-11-01: the newest version among the datasets listed above.

Districts nearest SW1A

• SW1Y0.4 km
• SW1H0.7 km
• WC2N0.7 km
• SW1E0.9 km
• W1J1.0 km
• W1D1.0 km
• W1S1.0 km
• WC2E1.0 km
• WC2H1.0 km
• W1F1.0 km
• W1B1.2 km
• WC2R1.3 km
• Every district
• How a British address is written
• Check any address

distance between the districts' centroids