CM21 postcode district
CM21, in the CM (Chelmsford) postcode area, has 319 live and 165 terminated postcodes in the ONS Postcode Directory of August 2026, and OS Open Names files 161 roads under it.
| postcode area | CM (Chelmsford) |
|---|---|
| live postcodes | 319 |
| terminated postcodes | 165 |
| sectors | 3 |
| roads listed | 161 |
| companies registered | 1,444 |
| centroid | 51.81249, 0.14505 |
| directory release | 2026-08 |
Postcodes and sectors
319 of the district's 484 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 51.81249, 0.14505, which locates the district, not a building.
| sector | live | terminated |
|---|---|---|
| CM21 0 | 136 | 41 |
| CM21 1 | 8 | 37 |
| CM21 9 | 175 | 87 |
Companies registered in CM21
Companies House lists 1,444 companies with a registered office in CM21; 331 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 CM21
- Eastern
- East Hertfordshire
- Hertfordshire
- Sawbridgeworth
- Epping Forest
- Essex
- High Wych
- Allen's Green
Roads filed under CM21
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.
- Alders Walk
- Applegate
- Ash Groves
- Atherton End
- Bakers Walk
- Barnard Road
- Barrett Drive
- Beanfield Road
- Beech Drive
- Beechfield
- Bell Mead
- Bell Street
- Blacksmiths Way
- Blenheim Close
- Bluebell Walk
- Bonks Hill
- Broadfields
- Brook End
- Brookfields
- Brook Lane
- Brook Road
- Bullfields
- Burnside
- Buttersweet Rise
- Cambridge Road
- Camp Drive
- Cedar Close
- Chalks Avenue
- Chandlers Lane
- Chaseways
- Cherry Gardens
- Church Street
- Church Walk
- Clements Street
- Coney Gree
- Covey's Lane
- Crofters
- Crofters End
- Cutforth Road
- Dale Court
- Dorrington Place
- Dovedale
- Duckling Lane
- Durham Close
- East Drive
- East Park
- Elmwood
- Fairway
- Falcon Close
- Falconers Park
- Farnham Close
- Forebury Avenue
- Gangies Hill
- Giffin Way
- Gilders
- Greenstead
- Hailey Place
- Hallingbury Road
- Hampton Gardens
- Hand Lane
all 161 roads
- Harlow Road
- Hedgerows
- Heron Close
- Highgate Grove
- High Wych Lane
- High Wych Road
- Hill Tree Close
- Hoestock Road
- Honeymeade
- Hornby Way
- Kecksy's
- Kelly Gardens
- Kingsmead
- Knight Street
- Ladywell Prospect
- Law Close
- Lawrence Avenue
- Lawrence Moorings
- Leat Close
- Linwood
- London Road
- Lowfield
- Luxford Place
- Mabey's Walk
- Mansfield
- Marlands
- Maylins Drive
- Meadow Way
- Merefield
- Millfields
- Mill Lane
- Monk Road
- Moorlands Reach
- Newports
- New Street
- Newton Drive
- Northfield Road
- Nursery Fields
- Oak Drive
- Oak Walk
- Parkway
- Paynter Crescent
- Pishiobury Drive
- Potters Mews
- Puncher Drive
- Queen's Close
- Redricks Lane
- Reedings Way
- Revell Crescent
- Riverfield Lane
- Rochester Avenue
- Roman Rise
- Roseacres
- Rowan Walk
- Rowney Gardens
- Rowney Wood
- Rushfield
- Sacombs Ash Lane
- Saffron Crescent
- Salmon Road
- Sappers Close
- Sayesbury Avenue
- Sayesbury Road
- Sayes Gardens
- School Lane
- Sheering Lower Road
- Sheering Mill Lane
- Slater Lane
- Southbrook
- Springhall Lane
- Springhall Road
- Station Road
- Stoneleigh
- Sun Street
- The Crest
- The Drive
- The Forebury
- The Four Acres
- The Limes
- The Meadows
- The Mews
- The Orchards
- The Square
- Tobin Lane
- Truswell Crescent
- Vantorts Close
- Vantorts Road
- Walker Place
- Wallen Park
- Walnut Tree Avenue
- Walnut Tree Crescent
- West Road
- Wheatley Close
- White Post Field
- Willow Mead
- Wimborne Close
- Wisemans Gardens
- Woodward Gardens
- Wychford Drive
- Yewlands
- A1184
Check an address in CM21
The same road list through the API, from the outward code alone:
curl "https://spaw.co/api/v1/address/streets?country=GB&postal_code=CM21" \ -H "Authorization: Bearer $SPAW_KEY"
Common questions about CM21
- What does a CM21 postcode tell you?
- That the address lies in the CM21 district of the CM (Chelmsford) postcode area, and the place OS Open Names most often lists first for its postcodes is Sawbridgeworth. The district alone does not place a street: the inward half of the full postcode narrows the address to one of the district's 319 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 CM21
- CM174.3 km
- CM205.0 km
- SG106.1 km
- CM236.8 km
- CM186.9 km
- CM927.5 km
- CM197.8 km
- CM228.4 km
- CM2410.5 km
- SG1211.1 km
- SG1111.2 km
- EN1111.8 km
- Every district
- How a British address is written
- Check any address
distance between the districts' centroids
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