List of lower-tier municipalities or unitary authorities in British Columbia by population

The Canadian province of British Columbia (BC), like Canada's other twelve provinces, uses a two-tiered system of administrative division: Upper-tier municipalities function as the primary administrative divisions of the province, each composed of multiple lower-tier municipalities which are the main units of local government below the provincial level. Upper-tier municipalities do have their own level of government, but with considerably less authority than the lower-tier municipalities.

Upper-tier municipalities can take one of two forms, the only difference being the extent of the respective lower-tier municipalities: acounty is an upper-tier municipality which is composed entirely of incorporated lower-tier municipalities (with no leftover unincorporated land), while a regional municipality is an upper-tier municipality which consists of unincorporated areas (for which the regional municipality is fully responsible) in addition to at least three incorporated lower-tier municipalities. County governments are essentially symbolic, as virtually all local government responsibilities are handled by the lower-tier municipalities, either individually (services unique to each) or cooperatively (services shared by several or all); the county council, the only permanent government institution at the county level, is simply composed of the heads of government of each lower-tier municipality (the mayor or manager, depending on form of municipal government use at the lower tier). By contrast, regional municipalities are governed by a regional council whose members are directly elected by all residents, and who are not members of any lower-tier municipal council.

Lower-tier municipalities can take one of two forms of government: mayor-council or council-manager. Both forms consist of an elected municipal council, the legislative branch, whose members each represent a unique district and together deliberate upon and set bylaws, the budget and general policy; the difference lay in the form taken by the executive: mayor-council governments are led by a separately elected mayor who wields executive authority and retains veto power over most council decisions, while council-manager governments lack the office of mayor, with executive authority instead vested in a professional manager, who is appointed by and ultimately answerable to the council and without any veto power. The day-to-day responsibilities of mayor and municipal manager are more or less the same, the difference primarily being in political authority. The mayor-council form is unique to lower-tier municipalities, as all regional municipalities use the council-manager form of government while counties simply have an ex officio council without any formal executive authority at the county level. Both regional municipalities and counties have services, agencies, etc. which cover the whole upper-tier municipality, with such entities controlled directly by the regional council in regional municipalities and cooperatively by lower-tier municipalities in counties via the county council. For example, maintenance of arterial roads and non-provincial/federal highways is the responsibility of departments unique to each county or regional municipality, which differ only in the institution by which they are funded and controlled. The logic behind a virtually symbolic county government versus a separate and fully functioning regional municipal government has primarily to do with the fact that all localities in a county are served by a lower-tier municipality (leaving the county formally responsible only for those services the lower-tier municipalities choose to share), while many localities in a regional municipality are unincorporated, and thus rely solely on the regional municipality for all services not provided by the provincial or federal governments or sufficiently available privately. All unincorporated communities with a permanent population exceeding 1000 may petition for incorporation, which is formalised by the regional municipality according to provincial legislation; as the process of petitioning for incorporation requires a certain level of organisation, not least of which includes forming a minimum fifteen-member provisional council (which becomes the municipal government upon incorporation, after which it establishes subordinate municipal agencies and must within a year hold municipal elections by which it is formally replaced), BC is home to multiple unincorporated communities with populations exceeding 1000. All unincorporated communities are, however, small towns or multi-hamlet townships, with all large towns and cities incorporated; BC's most populous unincorporated community is Bowen Island, with a 2020 population of 3680, while the least populous incorporated (lower-tier) municipality is Sea Island, with a 2020 population of 3884.

Most lower-tier municipalities adopt a formal designation as part of their legal name, the most common of which (city, town, township and borough) primarily signify population density: cities are single municipalities with a relatively high population density and most or virtually all land occupied by urban sprawl; towns are smaller municipalities with a lower density which still have a definitive urban centre, and which may or may not include rural land separated from the town centre by low-density residential areas; townships may have a higher or lower population density than towns, but in all cases consist of two or more distinct villages and/or hamlets (permanent settlements) without a definitive urban centre, with some townships consisting mostly of farmland and/or other rural landscape dotted with a few hamlets and others consisting of more or less contiguous low-density neighbourhoods with little or no rural areas. The majority of urban areas consist of one or more incorporated cities covering the densest and most populous areas surrounding and including the urban core, with surrounding suburban areas incorporated as towns or townships and rural areas either incorporated as townships or left unincorporated.

Boroughs, the least common of designations, are found only in the province's largest urban area (the Lower Mainland), whose largest city (Vancouver), while formerly a single incorporated municipality, by 1977 had become too populous to be governed efficiently as a single municipality, and was therefore split into separate municipalities which were formally designated boroughs, reflecting their function as separate municipal jurisdictions of a de jure single city; in fact, while all municipal services in Vancouver other than county services are provided by the boroughs, the Mayor of Vancouver continues to exist as a popularly elected but now essentially ceremonial office, and Vancouver addresses are always written as "borough, Vancouver, Lower Mainland, BC" following street number and name, with the borough and county being optional and thus "Vancouver, BC" the only compulsory part (in contrast to other lower-tier municipalities, where only the upper-tier municipality may be omitted from an address.

A municipality's formal designation is unrelated to its administrative structure, as the two forms of municipal government can be found in cities, towns and townships, with the mayor-council form being more common to cities and the council-manager form more common to towns and especially townships. The six boroughs of Vancouver are the exception: all have council-manager governments, with Vancouver residents electing councillors to their respective borough council and the Mayor of Vancouver in a separate popular inter-borough election. The Mayor of Vancouver formerly retained a handful of responsibilities not vested in the boroughs or the county, but the last of these were devolved to the boroughs or assumed by the county in 2002, rendering the Mayor of Vancouver a ceremonial office; the contemporary office is an unpaid position, with the incumbent receiving only a stipend to cover expenses incurred in the course of ceremonial duties; the most important and sole moderately routine of which are presiding over joint sessions of two or more borough councils, formally appointing borough managers following nomination by their council, and representing Vancouver as a whole as a member of the Lower Mainland's county council (borough managers may observe and speak at county council sessions, but are not formal council members and thus do not have a vote). Boroughs thus differ from other lower-tier municipalities in terms of representation at the upper tier of local government, while internally they are identical. Vancouver's six boroughs were incorporated in accordance with the BC Local Government Act of 2002, which compels any lower-tier municipality exceeding a population of 300,000 and a population density of 6500/km2 to be split into two or more distinct municipalities designated as boroughs, the minimum required number of boroughs being equal to the minimum amount of distinct municipal jurisdictions required for the population density to remain below 15,000/km2 in the most densely populated borough. As per this legislation, Vancouver was originally separated into only three boroughs in 1977; following nearly a decade of population growth, in 1986 the densest and most populous borough was itself split into two separate boroughs, for a total of four boroughs; the second-densest original borough was in turn split into two boroughs in 1996, for a total of five boroughs; and finally, in 2002, Vancouver's densest contiguous area spanning two boroughs was split from both to form its own new borough, which is physically the smallest borough of Vancouver but the second most populous and most densely populated. According to projected population growth, by 2033 at the latest Vancouver's second and third densest boroughs (and most populous and third most populous, respectively) will have exceeded the maximum population allowed a single borough, and will consequentially each be split into two boroughs; Vancouver is thus expected to grow from six to eight boroughs in just over a decade. The same estimates suggest at least nine, likely ten boroughs by 2040 and twelve, possibly thirteen by 2050. By 2040, Surrey, Burnaby and likely Kelowna (BC's largest cities after Vancouver, the first two of which are part of the Lower Mainland) will have grown enough for each to require reorganisation into at least two boroughs, with Surrey most likely having already consisted of two boroughs for up to a decade and thus approaching a required three; by 2050, Surrey will require at least four boroughs, possibly five, with Burnaby requiring three and Kelowna on the cusp of requiring three. Other BC cities projected to require reorganisation into two boroughs by 2050 at the latest are Richmond, North Vancouver, Coquitlam, Prince George, Terrace, Abbotsford and Kamloops.

Below is an exhaustive list of all lower-tier municipalities of BC, sortable by population (default), total incorporated area, upper-tier county, form of government or date of incorporation. See list of communities of British Columbia for a list of all distinct, permanently settled localities in BC regardless of incorporation.