CM1 postcode district

Postcodes and sectors

1,561 of the district's 2,801 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 51.74748, 0.45830, which locates the district, not a building.

Companies registered in CM1

Companies House lists 5,908 companies with a registered office in CM1; 1,330 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 CM1

• Essex
• Eastern
• Chelmsford
• Writtle
• Broomfield
• Uttlesford
• Roxwell
• Good Easter
• High Easter
• Loves Green
• Chignall St James
• Edney Common
• Mashbury
• Boyton Cross
• Cooksmill Green
• Chalk End
• Stagden Cross
• Pepper's Green
• Clatterford End
• Farmbridge End
• Chignall Smealy

Roads filed under CM1

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.

• Abbess Close
• Acer Grove
• Acres End
• Admiral Mews
• Admirals Walk
• Alamein Road
• Alan Cherry Drive
• Albany Close
• Albemarle Link
• Albert Bausor Close
• Aldeburgh Way
• Alick Horsnell View
• All Saints Close
• Alma Drive
• Alyssum Close
• Anderson Avenue
• Andrews Place
• Anjou Green
• Anvil Way
• Arbour Lane
• Armistice Avenue
• Arnhem Road
• Arthur Ashby Court
• Arthur Court
• Arthur Jupiter Place
• Arthur Turp Close
• Arun Close
• Ashford Place
• Ashford Road
• Ash Tree Close
• Ash Tree Crescent
• Ashurst Drive
• Aster Court
• Aubrey Close
• Auckland Close
• Avon Road
• Ayletts
• Back Lane
• Back Road
• Baker Road
• Banham Drive
• Bardell Close
• Barkis Close
• Barnaby Rudge
• Barnfield Mews
• Barn Green
• Barrack Road
• Baynes Place
• Beach's Drive
• Beardsley Drive
• Beauchamps Close
• Beaulieu Boulevard
• Beaulieu Parkway
• Beaumont Walk
• Beeches Close
• Beeches Court
• Beeches Crescent
• Beeches Road
• Begonia Close
• Bellmead

Check an address in CM1

Check an address in CM1

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

curl "https://spaw.co/api/v1/address/streets?country=GB&postal_code=CM1" \
  -H "Authorization: Bearer $SPAW_KEY"

Common questions about CM1

What does a CM1 postcode tell you?

That the address lies in the CM1 district of the CM (Chelmsford) postcode area, and the place OS Open Names most often lists first for its postcodes is Chelmsford. The district alone does not place a street: the inward half of the full postcode narrows the address to one of the district's 1,561 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 CM1

• CM23.5 km
• CM984.2 km
• CM39.1 km
• CM49.3 km
• CM1213.6 km
• CM1113.8 km
• CM813.9 km
• CM7714.7 km
• CM514.7 km
• SS1115.5 km
• CM1515.6 km
• CM615.9 km
• Every district
• How a British address is written
• Check any address

distance between the districts' centroids