SG3 postcode district

Postcodes and sectors

206 of the district's 323 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 51.86031, -0.18250, which locates the district, not a building.

Companies registered in SG3

Companies House lists 438 companies with a registered office in SG3; none of them at an address 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 SG3

• Hertfordshire
• Eastern
• North Hertfordshire
• Knebworth
• Welwyn Hatfield
• Woolmer Green
• East Hertfordshire
• Datchworth
• Old Knebworth
• Bull's Green
• Nup End Green
• Stevenage

Roads filed under SG3

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.

• Abbots Close
• Badger Close
• Baines Lane
• Bellamy Close
• Bell Close
• Birch Road
• Bramfield Road
• Bridge Road
• Broadfield Road
• Brookbridge Lane
• Broom Grove
• Burnham Green Road
• Bury Lane
• Carvers Croft
• Cherry Close
• Coltsfoot Lane
• Crab Tree Road
• Creamery Close
• Dancote
• Datchworth Green
• Deanscroft
• Deard's End Lane
• Deards Wood
• Deeping Close
• Devey Close
• Driver's End Lane
• Dunnock Close
• Evergreen Close
• Foldingshott
• Garden Close
• Garden Road
• Gate House Close
• Gibbons Way
• Gipsy Lane
• Great Highfield
• Great Lawne
• Gun Lane
• Gun Meadow Avenue
• Gun Road
• Gun Road Gardens
• Hall Lane
• Hawkins Hall Lane
• Haygarth
• Hay Wains
• Heath Road
• Hitchin Lane
• Hollybush Lane
• Holly Road
• Hornbeam Spring
• Keiths Wood
• Kerr Close
• Kimptons Court
• Knebworth Park
• London Road
• Longmead
• Lytton Fields
• Manor Farm Stables
• Mardleybury Court
• Mardleybury Road
• Mardley Hill

Check an address in SG3

Check an address in SG3

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

curl "https://spaw.co/api/v1/address/streets?country=GB&postal_code=SG3" \
  -H "Authorization: Bearer $SPAW_KEY"

Common questions about SG3

What does an SG3 postcode tell you?

That the address lies in the SG3 district of the SG (Stevenage) postcode area, and the place OS Open Names most often lists first for its postcodes is Knebworth. The district alone does not place a street: the inward half of the full postcode narrows the address to one of the district's 206 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 SG3

• AL63.3 km
• SG24.3 km
• SG16.0 km
• AL86.6 km
• AL77.1 km
• SG148.4 km
• SG48.4 km
• SG1311.1 km
• AL1011.7 km
• AL412.3 km
• SG1212.5 km
• AL512.7 km
• Every district
• How a British address is written
• Check any address

distance between the districts' centroids