House numbering or naming In most English-speaking countries, the usual method of house numbering is an alternating numbering scheme progressing in each direction along a street, with odd numbers on one side (often west or south or the left-hand side leading away from a main road) and even numbers on the other side, although there is significant variation on this basic pattern. Many older towns and cities in the UK have "up and down" numbering where the numbers progress sequentially along one side of the road, and then sequentially back down the other side. Cities in
North America, particularly those planned on a
grid plan, often incorporate
block numbers, quadrants (explained below), and
cardinal directions into their street numbers, so that in many such cities, addresses roughly follow a
Cartesian coordinate system. Some other cities around the world have their own schemes. Although house numbering is the principal identification scheme in many parts of the world, it is also common for houses in the United Kingdom and
Ireland to be identified by name, rather than number, especially in villages. In these cases, the street name will usually follow the house name. Such an address might read: "Smith Cottage, Frog Lane, Barchester, Barsetshire, BZ9 9BA" or "Dunroamin, Emo, Co. Laois, Ireland" (fictional examples).
Quadrants In cities with Cartesian-coordinate-based addressing systems, the streets that form the north–south and east–west dividing lines constitute the
x and
y axes of a
Cartesian coordinate plane and thus divide the city into
quadrants. The quadrants are typically identified in the street names, although the manner of doing so varies from city to city. For example, in one city, all streets in the northeast quadrant may have "NE" prefixed or suffixed to their street names, while in another, the intersection of
North Calvert Street and
East 27th Street can only be in the northeast quadrant.
Street-naming conventions Street names may follow a variety of themes. In many
North American cities, such as
San Francisco, USA, and
Edmonton,
Alberta and
Vancouver,
British Columbia, streets are simply
numbered sequentially across the street grid.
Numbered streets originated in the United States in
Philadelphia by
Thomas Holme, who laid out the original plan for the city in 1683.
Washington, D.C. has its numbered streets running north–south and lettered or alphabetically named streets running east–west, while diagonal avenues are typically named after states. In
Salt Lake City, and many other
Utah cities, streets are in a large grid and are numbered in increments of 100 based on their location relative to the center of the city in blocks. A similar system is in use in
Detroit with the
Mile Road System. In some housing developments in North America and elsewhere, street names may all follow the same theme (for example, bird species), or start with the same letter. Streets in
Continental Europe, the
Middle East, and
Latin America are often named after famous people or significant dates.
Postal codes Postal codes are a relatively recent development in addressing, designed to speed the sorting and processing of mail by assigning unique numeric or alphanumeric codes to each geographical locality.
Postal alternatives to physical addresses For privacy and other purposes, postal services have made it possible to receive mail without revealing one's physical address or even having a fixed physical address. Examples are
post office boxes,
service addresses and
poste restante (general delivery). == Address format ==