An electoral district, sometimes called a constituency, riding, circumscription, electorate, or ward, is a geographical portion of a political unit, such as a country, state or province, city, or administrative region, created to provide the voters therein with representation in a legislature or other polity. That legislative body, the state's constitution, or a body established for that purpose determines each district's boundaries and whether each will be represented by a single member or multiple members.
Generally, only voters (constituents) who reside within the district are permitted to vote in an election held there. The district representative or representatives may be elected by single-winner first-past-the-post system, a multi-winner proportional representative system, or another voting method. The district members may be selected by a direct election under wide adult enfranchisement, an indirect election, or direct election using another form of suffrage.
Terminology
The names for electoral districts vary across countries and, occasionally, for the office being elected. The term constituency is commonly used to refer to an electoral district, especially in British English, but it can also refer to the body of eligible voters or all the residents of the represented area or only those who voted for a certain candidate.
In American English, the term congressional district is used. The term "congressional district" is largely used in the United States and is distinctive from legislative districts. In the United States, congressional districts were inscribed into the Constitution to ensure representation based on population. Conversely, state legislation declares that "legislative representation be (built upon) non-population related principles such as representation of counties, cities, or other geographical and political unit".Altman, M.1998. Traditional Districting Principles: Judicial Myths vs. Reality. Social Science History, 22(2), 117-139.)
In Canadian English, the term electoral district is used officially, but they are colloquially known as a riding or constituency. In some parts of Canada, constituency is used for provincial districts and riding for federal districts. In colloquial Canadian French, they are called ("counties"), while circonscriptions is the legal term. In Australian and New Zealand English, electoral districts are called electorates, while the term electorate refers to the entire body of voters.
In India, electoral districts are referred to as "Nirvācan Kṣetra" () in Hindi, which can be translated to English as "electoral area" though the official English translation for the term is "constituency". The term "Nirvācan Kṣetra" is used while referring to an electoral district in general irrespective of the legislature. When referring to a particular legislative constituency, it is simply referred to as "Kṣetra" along with the name of the legislature, in Hindi (e.g. 'Lok Sabha Kshetra' for a Lok Sabha constituency). Electoral districts for buli municipal or other local bodies are called "wards". Local electoral districts are sometimes called wards, a term also used for administrative subdivisions of a municipality. However, in the Republic of Ireland, voting districts are called local electoral areas.
District magnitude District magnitude refers to the number of seats assigned to each district, and in conjunction with number of districts, determines the number of district seats to be filled in an election. Staggered terms are sometimes used to reduce the number of seats up for election at any one time, when district magnitude is more than one.
The term "district magnitude" was first used by the American political scientist Douglas W. Rae in his 1967 dissertation The Political Consequences of Electoral Laws.
To have a higher district magnitude, either a legislative chamber needs to contain more members or the voters thereof needs to be divided into fewer, larger districts.
The district magnitude affects the ease or difficulty to be elected, as the effective threshold, or de facto threshold, decreases as the district magnitude increases in multi-member districts and plural districts. The number of votes that a candidate requires to be elected is smaller when a district elects more members. However that effect is dampened when the district uses a non-proportional or landslide-prone election system such as general ticket voting and plurality block voting. Where multi-member districts are used, threshold de facto stays high if seats are filled by general ticket or other pro-landslide party block system, although this is rarely used nationwide.
Duverger drew a correlation between proportional representation in multi-member districts and the number of parties (fragmentation). The results produced by different district magnitudes supports Duverger's observation that single-winner contests tend to produce two-party systems, and proportional representation (PR) methods tend to produce multi-party systems. However, some PR systems when used in small-sized multi-member constituencies, of DM of less than 5 for example, sometimes produce a small number of effective parties. Malta diverges from Duverger's rule. It uses DM-5 districts and has a two-party system.
Even first past the post election systems can produce multi-party legislatures. In Canada and several other countries, elections that use first-past-the-post system election system sometimes elect members of five different parties due to local conditions in the multitude of separate micro-battles across a country.
Contests with district magnitude of 1 mostly use plurality voting in single-member districts (first-past-the-post voting) but instant-runoff voting or the two-round system is used in other cases. In both systems each voter has one vote in the round of voting.
District magnitude is larger than 1 where multiple members are elected (plural districts), and such districts have available a wide variety of election methods. Such districts usually use one of these systems: plurality block voting (where voter may cast as many votes as the number of seats to be filled), list proportional representation, single transferable vote elections (where each voter casts just one transferable vote). Limited voting and single non-transferable vote are used less often. In other cases, each seat in the multi-seat district is filled through a separate contest, usually through first-past-the-post. Canada's Prince Edward Island elected all its members using the post/seat system and first past the post for many decades. Another Canadian province, British Columbia, used instant-runoff voting and the seat/post system in multi-member districts in the early 1950s.
In list PR systems, district magnitude may exceed 100, but in many cases the average district magnitude under list PR is only about 14. In elections under single transferable vote systems, district magnitude normally ranges from 2 to 10 members in a district. Sometimes STV uses a greater district magnitude than that. Examples are at-large optional preferential elections in New South Wales Legislative Council (district magnitude of 21) and the 2025 Western Australian Legislative Council (district magnitude of 37).
District magnitude is maximized where: jurisdictions with a single electoral district for the whole elected body (at-large voting). This includes the legislatures of: the Netherlands (1 district for population 13 million and 150 seats), Serbia (7 million, 250 seats), Israel (10 million, 120 seats), Slovakia (4 million, 150 seats), and Moldova (3 million, 101 seats). In each of these cases, it takes less than a percentage point of the nation's electorate to capture a seat. systems use a two-tier form of party-list proportional representation, using both local multi-member constituencies (of various district magnitudes and seat-to-vote ratios), and national levelling seats where parties' nationwide vote tallies have priority (Mixed-Member Proportional). That is the case in Scandinavia: Sweden (population 6.5 million, 349 seats, 29 districts, see national apportionment of MP seats in the Riksdag article), Denmark (4 million, 179 seats, 12 districts), Norway (4 million, 169 seats, 19 districts), and Iceland (0.2 million, 63 seats, six districts). systems use a two-tier form of party-list proportional representation, using both local single-member districts, and national levelling seats, when the parties' nationwide vote tallies have priority (Mixed-Member Proportional). New Zealand uses such an MMP system. systems use a three-tier form of party-list proportional representation, using both local single-member districts, and state and national levelling seats, to produce proportional representation in each state and nationwide based on party votes cast by voters (Mixed-Member Proportional). From 2017 to 2023, in elections of Germany's Bundestag, additional members were allocated to make up for overhang seat won by parties and parties were allowed to win single-member-district seats even if not proportionally due them. After 2023, a party is allowed to take only as many seats as its proportion of the second vote (party vote) allows. If it elects too many single-member-district seats, they are disallowed, and the seats are allocated to another party.
DM is moderate where many districts break up the electorate or where relatively few members overall are elected, even if the election is held at-large. District magnitude may be set at an equal number of seats in each district. Examples include: all districts of the Northern Ireland Assembly elect 5 members (6 members prior to 2017); all those of the Parliament of Malta elect 5 MPs; all those of the Welsh Assembly elect 6. Chile, between 1989 and 2013, used a method called binomial voting, which assigned 2 MPs to each district. Most countries that use proportional representation use multi-member constituencies correspond to already existing jurisdictions (regions, districts, wards, cities, counties, states or provinces), which creates differences in district magnitude from district to district"District Magnitude", International Encyclopedia of Elections (2000), p. 67: Republic of Ireland for the Dáil Éireann: 3-, 4-, and 5-member districts. (STV is used) (historically district magnitude in Irish districts has been as large as 8 (1921-1937).) Hong Kong for half of the Legislative Council of Hong Kong: 5- to 9-member districts. The New Hampshire House of Representatives: 1- to 10-member districts (Plurality block voting is used). South Africa 27 million registered voters and 400 seats (with 200 filled in nine provincial-wide districts using party lists, and 200 elected according to PR. Provincial representation in the National Assembly, elected in province-wide districts, ranges from 5 seats in the Northern Cape to 48 seats in Gauteng.
Where districts have the same vote-to-member ratio, the number of votes needed to be elected are very similar district to district, irrespective of the district magnitude in the district. Proportional representation in a district elects multiple members who represent a variety of opinion, and therefore relatively few votes are wasted. To further avoid the waste of votes, transferable ranked votes are used in addition to the election of multiple members. A quota, a set proportion of votes as a minimum, assures the election of a candidate and allows surplus votes to go to where they might be useful. In such elections, a large proportion of votes are used to elect someone. The quota is often set as the inverse of the district magnitude plus one, plus one, the Droop quota. Droop is the mathematical minimum whereby no more can achieve quota than there are seats to be filled. Such calculation is rendered un-necessary if even one vote is exhausted or rejected during the count process, in which case an even lower quota might be equally justifiable.