The DL postcode area covers Darlington and much of the Tees Valley and North Yorkshire dales across around 17 districts (DL1–DL17). Every DL address is held in Royal Mail's Postcode Address File (PAF), which spans about 31 million UK addresses across roughly 1.8 million postcodes. AutoPostcode returns DL results in under 100ms, free to try with no card required.
Live results from Royal Mail's Postcode Address File (PAF).
How does DL postcode work?
A DL postcode matches a full or partial postcode against Royal Mail's Postcode Address File (PAF), the UK's official address database of around 31 million addresses across roughly 1.8 million postcodes. You type a DL postcode, AutoPostcode returns every deliverable address at that location in milliseconds, and the user selects the correct one — no manual typing, no typos.
AutoPostcode's DL data is drawn from the same national PAF file used by Royal Mail, so a lookup in DL is as accurate as anywhere else in the UK. Integrate it through our postcode lookup API or drop the widget into any checkout with a few lines of code.
Which postcodes does DL use?
The DL postcode area is anchored on Darlington, running from DL1 in the town centre out to Northallerton (DL6–DL7), Richmond (DL10–DL11), Bishop Auckland (DL13–DL14) and Barnard Castle (DL12). All DL districts resolve against Royal Mail PAF.
Why use AutoPostcode for DL address lookup?
- Royal Mail PAF-backed data covering every deliverable DL address
- Sub-100ms responses so checkout never stalls
- Simple, affordable pricing — a modern alternative to Loqate, Fetchify and Ideal Postcodes
- Developer-friendly REST API with drop-in front-end widget
- GDPR-compliant, UK-hosted lookups
How does AutoPostcode compare to other lookup tools?
| Feature | AutoPostcode | Typical incumbent |
|---|---|---|
| Data source | Royal Mail PAF | Royal Mail PAF |
| DL coverage | Full | Full |
| Pay-as-you-go | Yes | Often minimums |
| Free trial | Yes, no card | Rarely |
| Setup time | Minutes | Hours/days |
Get started with DL postcode
Try the free lookup above, then wire AutoPostcode into your site with the UK address validation API for full validation, or the postcode lookup API for autocomplete. You can also explore the full product range to see nationwide coverage beyond DL.
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Frequently asked questions
What is the DL postcode area?
The DL postcode area is the group of postcodes centred on Darlington in north-east England, covering the town and much of the Tees Valley, North Yorkshire dales and southern County Durham. Every deliverable DL address is held in Royal Mail's Postcode Address File (PAF).
Which towns does the DL postcode cover?
The DL postcode area covers Darlington, plus Northallerton, Richmond, Bishop Auckland, Barnard Castle, Catterick, Shildon and Newton Aycliffe.
How many districts are in the DL postcode area?
The DL postcode area has around 17 postcode districts (DL1 to DL17), spanning Darlington, the Tees Valley and the North Yorkshire dales.
Is the DL postcode address data accurate?
Yes. AutoPostcode uses the official Royal Mail PAF, which holds around 31 million UK addresses across roughly 1.8 million postcodes, including every deliverable DL address.
How fast is a DL postcode lookup?
AutoPostcode returns DL postcode address results in under 100 milliseconds, keeping checkout and form autocomplete instant.
Can I try the DL postcode lookup for free?
Yes. Use the free demo on this page, then start a free trial with no credit card to integrate it into your own website.
How do I add a DL postcode lookup to my site?
Use the AutoPostcode postcode lookup API or drop-in widget — most sites integrate it in minutes with a few lines of code.
Ready to get started?
Add Royal Mail PAF-verified UK address lookup to your site in minutes — start free, no card required.