What area is the HA4 postcode in?

HA4 is a postcode district in Harrow, Harrow, London, England. It is part of the HA postcode area.

How many addresses are in the HA4 postcode?

The HA4 postcode district covers Harrow in Harrow. The exact address count can be retrieved via the APITier Postcode Lookup API.

How do I look up addresses in HA4 programmatically?

Use the APITier Postcode Lookup API: GET https://postcode.apitier.com/v1/postcodes/{postcode}?x-api-key=YOUR_KEY — where the postcode begins with HA4. The response returns all PAF addresses as structured JSON including building name, number, street, town, county, and geocoordinates.

Royal Mail PAF · London

HA4 Postcode — Harrow

HA4 is a postcode district in Harrow, Harrow, London, England. Use the lookup below to explore addresses within this postcode district.

HA4

Postcode District

HA — Harrow

Area

London

Region

Royal Mail PAF

Data Source

Postcode Lookup — HA4 DistrictSample

{
  "_note": "Sample response — enter any postcode above and click Lookup for live data",
  "status": 200,
  "result": {
    "postcode": "HA4 1AA",
    "quality": 1,
    "eastings": 520778,
    "northings": 236025,
    "country": "England",
    "nhs_ha": "London",
    "longitude": -0.2746,
    "latitude": 51.5768,
    "european_electoral_region": "London",
    "primary_care_trust": "Harrow",
    "region": "London",
    "lsoa": "Harrow 001A",
    "msoa": "Harrow 001",
    "incode": "1AA",
    "outcode": "HA4",
    "parliamentary_constituency": "Harrow",
    "admin_district": "Harrow",
    "parish": "Harrow, unparished area",
    "admin_county": null,
    "admin_ward": "Harrow Central",
    "ced": null,
    "ccg": "NHS London",
    "nuts": "Harrow",
    "codes": {
      "admin_district": "E07000000",
      "admin_county": "E99999999",
      "admin_ward": "E05000000",
      "parish": "E43000000",
      "parliamentary_constituency": "E14000000",
      "ccg": "E38000000",
      "lsoa": "E01000000",
      "msoa": "E02000000"
    }
  }
}

About the HA4 Postcode District

The HA4 postcode district is part of the Harrow (HA) postcode area, covering Harrow and surrounding areas in London, England.

Postcodes in the HA4 district follow the format HA4 nXX where n is a digit and XX are letters. Each inward code identifies a specific delivery walk within the district.

The wider Harrow postcode area (HA) also covers: Wembley, Northolt, Ruislip, Pinner, Stanmore.

Frequently Asked Questions

What area does the HA4 postcode cover?

The HA4 postcode district covers Harrow in Harrow, London, England. It is one of 10 districts in the HA postcode area.

How do I look up all addresses in the HA4 postcode?

Use the live lookup widget above or call the APITier Postcode Lookup API: GET https://postcode.apitier.com/v1/postcodes/{full postcode}?x-api-key=YOUR_KEY. Replace {full postcode} with any complete postcode beginning HA4. The API returns all Royal Mail PAF addresses as structured JSON.

Is HA4 a valid UK postcode district?

Yes. HA4 is a Royal Mail postcode district in Harrow, England. Full UK postcodes in this district follow the format HA4 followed by a digit and two letters (e.g. HA4 1AA).

HA4 Postcode — Harrow

About the HA4 Postcode District

Frequently Asked Questions

Other Harrow Postcode Districts