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Breaking Down UK Address Data

What Is a Locality? What Is a Thoroughfare? Some Common UK Address Questions Answered

Updated 18 Jan 2021

UK addresses can be a bit complex. We’ve compiled a number of frequently asked questions about UK addresses that can be helpful in understanding Royal Mail PAF data.

What is a Locality?

A locality is a geographical area which includes a dependent locality, a double dependent locality, post town or county.

What is a Dependent Locality?

A dependent locality is an address element that distinguishes a premise when an address thoroughfare appears more than once in the same post town. PAF holds details of approximately 30,000 localities within the UK.

For example, the dependent locality of the sector TN23 8 is Chilmington Green.

For more precise data, you may find a double dependent locality. This is usually a business park or estate. For example, the dependent locality for the sector BH24 2 is Matchams and the double dependent locality is Silver Mist Park.


  • Only one Locality per postcode
  • Double dependent locality can only be present when a dependent locality is present
  • Post town is always present in every address and is important for the delivery point of an address

What is a Thoroughfare?

A thoroughfare is a main road or passageway.

What is a Dependent Thoroughfare?

A dependent thoroughfare distinguishes a premise when a thoroughfare appears more than once in a post town. When a thoroughfare is present there is always street level data available for the address.


  • Thoroughfare can me made up of both thoroughfares and dependent thoroughfares
  • A dependent thoroughfare can include both a dependent thoroughfare name and a dependent thoroughfare descriptor
  • Each postcode can only have one thoroughfare.
  • A dependent thoroughfare cannot be present on its own and when present there is always thoroughfare information available
  • A thoroughfare isn’t always required

What is a Post Town?

Post towns were created by Royal Mail to correctly route mail to the correct sorting office for any given address. Post towns are mandatory to identify an address.

Post towns may not necessarily map to the nearest geographical town.

There are 1661 Post Towns in the UK.

Address Data

For more address terms, please take a look at our glossary.