House numbering

The first record of a house numbering system in Paris dates to the 15th century. On March 1, 1768, King Louis XV decreed that all houses outside of Paris were to be assigned a number to help locate the soldiers residing in civilian houses. On February 4, 1805, Napoleon I announced that in Paris for house numbering a distinction should be made between even numbers (on the right side) and odd numbers (on the left side); the direction of the streets is oriented from upstream to downstream for streets parallel to the Seine, and from the banks to the north and south for streets oblique or perpendicular to the Seine. Such a system quickly became common in large cities across France.[13][14]

A ruling in 1994 obliged French communes with a population of 2,000 or more to number their houses. Sequential numbering, common in cities, mimics the system used in Paris. But many small villages used the numbering which takes a central village point — often the town hall — and works outward (a house that is 200 metres along the road from point zero will be numbered 200, its nearest neighbour, perhaps 270 metres from the centre, becomes number 270, etc.)[15]

The Finnish numbering system incorporates solutions to the problems which arose with mass urbanization and increase in building density. Addresses always are formatted as street name followed by street address number. With new, infill building, new addresses are created by adding letters representing the new ground level access point within the old street address, and if there are more apartments than ground level access points, a number added for the apartment number within the new development. The original street numbering system followed the pattern of odd numbers on one side and even numbers on the other side of the street, with lower numbers towards the center of town and higher numbers further away from the center.

The infill numbering system avoids renumbering the entire street when developments are modified. For example, Mannerheimintie 5 (a large mansion house on a large city plot) was demolished and replaced with 4 new buildings each with 2 stairwells all accessible from Mannerheimintie. The 8 new access stairwells are labelled A B C D E F G and H (each with the letter visible above the stairwell). Each stairwell has 4 apartments on 5 floors, so the new development has 160 new addresses in all running from Mannerheimintie 5 A 1 through to Mannerheimintie 5 H 160. The opposite example is where old, narrow buildings have been combined; Iso Roobertinkatu 36, 38 and 40 were demolished in the 1920s and the new building has the address Iso Roobertinkatu 36–40.

In the rural parts of Finland, a variant of this method is used. As in towns, odd and even numbers are on opposite sides of the road, but many numbers are skipped. Instead, the house number indicates the distance in tens of metres from the start of the road. For example, "Pengertie 159" would be 1590 metres from the place where Pengertie starts.

When more buildings are constructed than numbers were originally allotted, discontinuity of numbering is avoided by giving multiple adjacent buildings the same number, with a letter suffix starting at "A". The "Bis" suffix is used occasionally. Each house or apartment can be uniquely identified by a combination of a postcode, a street number and a suffix. Apartments within the same building can be distinguished various ways: by assigning each apartment their own street number, by assigning a simple prefix (generally a letter) or by assigning a complex prefix that takes into account both the floor and the apartment on the floor (e.g. B3). In Haarlem, Netherlands, red numbers are used for upstairs apartments.

In Portugal, the European scheme is most commonly used. However, in Porto and several other cities in the Portuguese Northern region, as well as in the Cascais Municipality (near Lisbon), houses are numbered in the North American style, with the number assigned being proportional to the distance in meters from the baseline of the street.

Lisbon numbering is European and furthermore 'from the river, odd numbers left'. Because the Tagus borders Lisbon on the south and the east, this means that north–south streets are numbered low from the south, and east–west streets are numbered low from the east.

In many new planned neighborhoods of Portugal houses and other buildings are identified by a lote (plot) number without reference to their street. This is in law the número de polícia, which literally means police's number – the police formerly assigned the numbers rather than the town hall. The lote is the construction plot number used in the urban plan, a consecutive number series applies to a broad neighborhood. In theory and in most cases, the use of a lote number system is provisional, being replaced by a traditional street number system some time after the neighborhood is built and inhabited. In some neighborhoods, lote numbers are kept for many years, some never being replaced by street numbers.

The relatively new planned neighborhood of Parque das Nações in Lisbon has also a different numbering scheme: each building is referred by its plot, parcel, and building (in Portuguese: lote, parcela, prédio[16]).

Clockwise scheme. A similar, counter-clockwise scheme also remains in use in parts of Germany.

The European system is most widely used. The odd numbers will typically be on the left-hand side as seen in the direction of increasing numbers (most commonly with the lowest numbers at the end of the street closest to the town or village centre). Intermediate properties usually have a number suffixed A, B, C, etc., much more rarely instead being given a half number, e.g. the old police station at 20+1⁄2 Camberwell Church Street. It is extremely rare for a property (built next to no. 2 after the street had been numbered) to be zero (0) or named Minusone; in 2013 researchers found these instances once in Middlesbrough and once in Newbury.[17] In 2022, starting to type "0," into the Royal Mail postcode search [18] revealed Middlesbrough had four listed properties, whilst Birmingham, Ellesmere Port, Lincoln and London have one each. In many rural streets, significantly built alongside before 1900, houses remain named and unnumbered.

In some places, particularly when open land, a river or a large church fronts one side, all plots on one side of a street are numbered consecutively. Such a street if modern and long is more likely to be numbered using odd numbers, starting at 1. Along oldest streets, numbering is usually clockwise and consecutive: for example in Pall Mall, some new towns, and in many villages in Wales. This often also applies to culs-de-sac and standalone terraces. For instance, 10 Downing Street, the official home of the Prime Minister, is next door to 11 Downing Street. Houses which surround squares, as well as market places, are usually numbered consecutively clockwise.

In the early to mid 19th century numbering of long urban streets commonly changed from clockwise (strict consecutive) to odds facing evens, particularly when roads were extended into new suburbs. Where this took place it presents a street-long pitfall to researchers using historic street directories and other records. A very rare variation may be seen where a high street (main street) continues from a less commercial part – a road which breaks the UK conventions by not starting at 1 or 2. On one side of the main road between Stratford and Leytonstone houses up to no. 122 are "Leytonstone Road". The next house is "124 High Road, Leytonstone".

In some villages, a single numbering system covers the entire settlement, especially in rural areas without formal street names. In this case the house number is appended directly to the village name in addresses. This often coexists with newer developments within the same village that use street names, e.g. "58 Dorfield" alongside "3 Church Close, Dorfield", although to avoid confusion the older houses may eventually gain street names of their own while keeping their numbers ("58 Axtley Road, Dorfield").

Developers may avoid the number 13 for house numbering as in Iran, because that number is considered by some to be unlucky.[19]

Blocks of flats (apartments) are treated in two ways:

• Flats numbered individually as part of the street. A lintel will typically be embossed or metalled "1–24 Acacia Avenue" or "Flats 1–24 Acacia Avenue".
• Flats numbered within a building. The building retains its own number (or name) on the street e.g. "Flat 24, 1 Acacia Avenue" or increasingly as commonly: "Apartment 9D, Newhouse Court, 1 Acacia Avenue". Outside the number of flats is discreetly shown or not revealed. Where flats are lettered, this can also be indicated by appending the letter to the building number: "Flat D, 1 Acacia Avenue" may also be "1D Acacia Avenue" (generally only one of these formats will be officially used).
• In some parts of Scotland, particularly Aberdeen and Dundee, flats in tenement blocks may be numbered as follows; "Flat 3/L, 1 Acacia Avenue". In this numbering system 3 refers to the floor (with G or 0 being used for the ground floor) and L or R indicating whether the flat is on the left or right from the entrance of the block.

In the UK street numbering and street signposts vary across local authorities. Numbering plates (or similar) are overwhelmingly at the discretion of house owners.

In the UK fanlights in front doors were introduced in the 1720s in which the house number may be engraved.[20] Contemporary architecture and modern house building techniques see alternatively acrylic, aluminium, or glass, ceramic, brass, slate, or stone used.

Italy mostly follows the European scheme described above but there are some exceptions, generally for historical reasons.

In Venice, houses are numbered within six named series (one per sestiere district). Similarly, small villages in rural areas may also occasionally use a single progressive series for all house numbers.[21]

In Genoa, Savona and Florence houses are marked with black (sometimes blue in Florence) numbers; businesses are usually (but not always) given red numbers, giving up to two distinct, numerically overlapping series per street. Those of businesses are denoted in all other writing (documents, online directories, etc.) by the addition of the letter "r" for rosso (e.g. "Via dei Servi 21r").

In most of Turkey, currently the European house numbering scheme is applied. The Istanbul Metropolitan Municipality introduced new house numbering and street signs in 2007 by two official designers.[22]

• 
  House number in Foça

A double numbering system has been used, similar to the system in the Czech Republic and Slovakia, which also were formerly parts of the Austro-Hungarian Empire.

Map of house numbering in the Prague district of Vyšehrad

In some Czech and Slovak cities and settlements, two numbering systems are used concurrently.

The basic house number is the "old" or "conscription number" (Czech: popisné číslo, Slovak: súpisné číslo). The conscription number is unique within the municipal part (a village, a quarter, mostly for one cadastral area) or within a whole small municipality.

For makeshift and recreational buildings in the Czech Republic, "registration number" (evidenční číslo) from a separate number series is used instead of the descriptive number. Typically, this number begins with zero or with the letter "E", or has different colour, or contains words like nouzová stavba ("makeshift structure") or chata ("weekend house"), etc.

In some settlements where streets have names (mostly in cities), "new" or "orientational numbers" (Czech: orientační číslo, Slovak: orientačné číslo) are also used concurrently. The orientational numbers are arranged sequentially within the street or square. If the building is on a corner or has two sides, it can have two or more orientation numbers, one for each of the adjacent streets or squares. Solitary houses distant from named streets often have no orientation number. In some places, the name of a small quarter is used instead of a street name. If there is a new building between two older numbered ones, the orientation number is distinguished with an additional lower case letter (for example, the sequence could be 5, 7, 9, 9a, 9b, 9c, 11, 13). In the 1930–1950s in Brno, lower case letters were used for separate entrances of modern block houses perpendicular to the street.

Either number may be used in addresses. Sometimes, businesses will use both numbers to avoid confusion, usually putting the descriptive (or registration) number first: "Hlavní 20/7". The two (or three) types of numbers are commonly distinguished by colour of the sign. Each municipality can have its own traditional or official rules and colours. In Prague and many other Bohemian cities, descriptive numbers are red, orientation numbers are blue and "evidential" numbers are green or yellow or red. In many Bohemian municipalities, descriptive numbers are blue, black, or are not unified. In Brno and some Moravian and Slovak cities, descriptive numbers are white-black signs, orientation numbers are red-white signs. Many cities and municipalities have different rules.

Formerly, Roman numerals signifying the city district were added to the conscription number: e.g. "125/III" means conscription number 125 in district number III (in Prague, this was Malá Strana). Roman numerals were used both in cities and in village municipalities with more settlements. Nowadays, the name of the settlement is preferred instead of Roman numerals.

The first conscription numbering was ordered by Maria Theresa in 1770 and implemented in 1770–1771. The series was given successively as the soldiers went through the settlement describing houses with numbers. Thereafter, every new house was allocated the next number sequentially, irrespective of its location. Most villages still use their original number series from 1770 to 1771. In cities, houses have been renumbered once or more often to be sequential – the first wave of renumbering came in 1805–1815. In 1857, the Austrian Emperor allowed a new system of numbering by streets. This new system was introduced in the biggest cities (Prague, Brno) in the 1860s. In 1884, land registration books were introduced and they used the old (conscription) numbers as a permanent and stable identifier of buildings. The new (orientation) numbers continue to be used concurrently.

In Germany, the European scheme (ascending odd/even numbers, see above) is usually used. In most cases, the numbers increase in the direction away from the town/city centre. Some places use a clockwise scheme for historical reasons, called Hufeisennummerierung ("horseshoe numbering") due to the progression of the numbers. This includes Berlin, parts of Hamburg and some other towns in northern Germany.

In some older streets in northern and eastern Germany, mainly in the former Kingdom of Prussia and adjoining areas, including parts of Berlin and Hamburg, the "horseshoe" numbering system (counter-clockwise "boustrophedon"-style numbering) was used for the numbering of new streets up until the 1920s, after which the European system was introduced for new streets.

Under the horseshoe numbering scheme, starting from one end, the buildings on the right side of the street were numbered sequentially from the near end to the far end of the street. The next number was then assigned to the last building on the left, opposite side of the street, the following numbers sequentially doubling back along the left side of the street. The building with the highest number would be the first on the left side, facing building number 1 across the street. The horseshoe numbering system remains in use in older streets in many German cities, notably Berlin, although newer adjoining streets may use modern European numbering. Kurfürstendamm in Berlin is a well-known example of a street where the horseshoe numbering scheme is still in use, although the numbering today starts with 11 at Breitscheidplatz, with number 237 across the street being the highest number.[23]

Very small villages sometimes number all buildings in the village sequentially according to their date of construction, and independent of the street they are on. However, this scheme is being phased out because it makes it hard to find a building by its address. [24]

In Russia and many other former USSR countries, the European style is generally used, with numbers starting from the end of the street closest to the town center. Buildings or plots at street intersections may be assigned a composite number, which includes the number along the intersecting street separated by a slash (Russian: дробь), like in Нахимова, 14/41 (14 is the number along Nakhimova street and 41 is the number along intersecting street).

The odd numbers are usually on the left side of the road, looking in the direction in which the numbers increase; though in some cities (including Saint Petersburg) the odd numbers are on the right side. Some cities (for example, Nizhniy Novgorod) have mixed numbering: odd numbers on the right in some parts of the city and on the left in others.

Soviet era housing districts (microdistricts) often have a complicated network of access lanes thought too small to merit their own names. Buildings in these lanes are ascribed to larger streets which may be quite far from their location; a building placed along a street may sometimes be ascribed to another street, which sometimes makes finding a building by its address a challenging task.

In some cities, especially hosting large scientific or military research centers in Soviet times, the numbering might be different: houses may have numbers related to the block rather than the street, thus 12-й квартал, дом 3 (Block 12, House 3),[25] similar to the Japanese and Korean systems. Aktau is one example of this.

When a numbered plot contains multiple buildings, they are assigned an additional component of the street address, called корпус (building), which is usually a sequentially assigned number unique within the plot (but sometimes contains letters as in 15а, 15б, 15в and so on). So, a Russian street address may look like Московское шоссе, дом 23, корпус 2 (Moscow Highway, plot 23, building 2), or улица Льва Толстого, дом 14Б (Leo Tolstoy Street, plot 14, building B).

On very long roads in suburban areas, a kilometer numbering system also may be used (like Australian rural numbering system). For example, 9-й км Воткинского шоссе (9th kilometer of Votkinsk Highway), and Шабердинский тракт, 7-й км (7th kilometer of Shaberdy Road).

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  In July 2010, after part of the existing street in Kyiv had been split off and renamed, the buildings got both new street names and new numbers.
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  Composite house numbers on street intersection, Veliky Novgorod

Many cities and civic groups have made efforts to improve street name and numbering schemes, such as Boston in 1879, Chicago in 1895, and Nashville in 1940 among others.[7] The street grid system of New York City, with its numbered streets and avenues, is attributed to the Commissioners' Plan of 1811. In Chicago, Edward P. Brennan worked in his spare time over 8 years to create a proposal to increase the efficiencies of the street name and addressing system, which was largely approved in 1909.[29][30] In Hollywood, Florida, Benjamin Israel worked for two and a half years to change three street names in the historic black district of Liberia from those that listed the names of Confederate soldiers in the American Civil War - Lee Street, Forrest Street, and Hood Street - to the names of Liberty Street, Freedom Street, and Hope Street. A local business owner had to supply the $20,000 funding to implement the change.[31] There are places in West Virginia which did not have named streets or addresses until at least 2013. After Verizon was caught inflating prices in 2002, Verizon reached an agreement with the state to supply $15 million to create at least 450,000 new street addresses.[32]

House numbering can be overhauled when a single addressing scheme replaces multiple local addressing schemes. An example from the 19th century is the house renumbering that occurred as part of the Georgetown street renaming in Washington, D.C.[33] In the 20th century, this occurred in places such as the New York borough of Queens[34] and Arlington County, Virginia.[35]