A post town is a required part of all postal addresses in the United Kingdom, and a basic unit of the postal delivery system. Including the correct post town in the address increases the chances of a letter or parcel being delivered on time. Post towns are usually based upon the location of delivery offices. Currently their main function is to distinguish between locality or street names in addresses not including a postcode.

There are approximately 1,500 post towns which are organised at the convenience of the Royal Mail. Each post town usually corresponds to one or more postal districts and each post town can cover an area including many individual towns and villages. Post towns rarely correspond to political boundaries and often group places that for all other purposes are quite separate.

In some places several post towns correspond to a single postal district with each post town covering one or more postcode sectors. There are anomalous examples where post towns and post codes do not coincide. For example, the post code sector EH14 5 is within three post towns: Juniper Green, Currie and Balerno, while Balerno is also within other sectors, such as EH14 7.

Post or POST may refer to:

A town is a human settlement larger than a village but smaller than a city. The size definition for what constitutes a "town" varies considerably in different parts of the world, so that, for example, many "small towns" in the United States would be regarded as villages in the United Kingdom, while many British "small towns" would qualify as cities in the United States.

The word town shares an origin with the German word Zaun, the Dutch word tuin, and the Old Norse tun. The German word Zaun comes closest to the original meaning of the word: a fence of any material.

In English and Dutch, the meaning of the word took on the sense of the space which these fences enclosed. In English, it was a small city that could not afford or was not allowed to build walls or other larger fortifications, and built a palisade or stockade instead (many early English settlements in North America used stockades.) In the Netherlands, this space was a garden, more specifically those of the wealthy, which had a high fence or a wall around them (like the garden of palace 't Loo in Apeldoorn, which was the example for the privy garden of William and Mary at Hampton Court). In Old Norse tun means a (grassy) place between farmhouses, and is still used in a similar meaning in modern Norwegian.