However, don't force users to supply postcode or region, they may not be used locally.

naming the settlement (city/town/village), which can be generically referred to as a locality

n general, a locality is a particular place or location. More specifically, a locality should be defined as a distinct population cluster. Localities are commonly recognized as cities, towns, and villages; but they may also include other areas such as fishing hamlets, mining camps, ranches, farms and market towns. Localities are often lower-level administrative areas and they may consist of sub-localities, which are segments of a single locality. Sub-localities should not be confused for being the lowest level administrative area of a country, nor should they be confused as being separate localities.

The regions in which a country is divided into. Each region typically has a defined boundary with an administration that performs some level of government functions. These areas are commonly expected to manage themselves with a certain level of autonomy. Various administrative levels exist that can range from “first-level” administrative to “fifth-level” administrative. The higher the level number is the lower its rank will be on the administrative level hierarchy. For example, the US is made up of states (first-level), which are divided into counties (second-level) that consist of municipalities (third-level). For comparison, the United Kingdom (GB) is comprised of the four countries England, Scotland, Wales and Northern Ireland (first-level). These countries are made up of counties, districts and shires (second-level), which in turn are made up of cities and towns (third-level) and small villages and parishes (fourth-level). Other common terms for an administrative area are administrative division, administrative region, administrative unit, administrative entity and subdivision.

In the United States of America, (US), we commonly use the terms city, state and zip code when referring to addresses. While that may mostly work for a country like Mexico (MX), it is not appropriate for other countries like Japan (JP) where the country is divided into prefectures instead of states. Not all countries call their sub-region divisions the same thing and many countries have several levels of sub-divisions. To further complicate the matter, not all sub-division levels are necessarily interchangeable from one country to another. For example, a first level sub-region in the US is a state, such as California (US-CA), but a first level sub-region for the United Kingdom of Great Britain and Northern Ireland (GB) is a country, such as England (GB-ENG).

Every country can have its own particular set of terms and definitions; to try to go over them all would be too complicated and inefficient. Instead, let’s go over some commonly used terms that are helpful when talking about international addresses.