Population centre (POPCTR)

Part A - Short definition:

Area with a population of at least 1,000 and no fewer than 400 persons per square kilometre.

The term 'population centre' (POPCTR) replaces the term 'urban area' (UA). Population centres are classified into three groups, depending on the size of their population:

• small population centres, with a population between 1,000 and 29,999
• medium population centres, with a population between 30,000 and 99,999
• large urban population centres, with a population of 100,000 or more.

Part B - Detailed definition:

A population centre (POPCTR) has a population of at least 1,000 and a population density of 400 persons or more per square kilometre, based on the current census population count. All areas outside population centres are classified as rural areas.

Taken together, population centres and rural areas cover all of Canada.

Population centres are classified into three groups, depending on the size of their population:

• small population centres, with a population between 1,000 and 29,999
• medium population centres, with a population between 30,000 and 99,999
• large urban population centres, with a population of 100,000 or more.

Population centre population includes all population living in the cores, secondary cores and fringes of census metropolitan areas (CMAs) and census agglomerations (CAs), as well as the population living in population centres outside CMAs and CAs.

Census years:

2011

Remarks:

Starting with the 2011 Census, the term 'population centre' replaces the term 'urban area.'

Prior to 2011, urban areas included a wide range of densely-populated areas, from small centres with a population of 1,000 to very large centres of more than 1 million. This approach ignored size differences by treating all urban areas as a single group. Given the widely accepted view that a more dynamic urban-rural continuum exists, the use of the term 'urban area' could lead to misinterpretations.

Population centres are divided into three groups based on the size of their population to reflect the existence of an urban-rural continuum.

The delineation rules for population centres (POPCTR) are ranked in order of priority:

1. The 2006 urban areas are retained as 2011 population centres if their current population is 1,000 or more.
2. If a dissemination block with a population density of at least 400 persons per square kilometre is adjacent to a population centre, then it is added to that population centre.
3. If a dissemination block or group of contiguous dissemination blocks, each having a minimum population of 1,000 and a population density of at least 400 persons per square kilometre for the current census, then the dissemination block or group of contiguous dissemination blocks is delineated as a new population centre.
4. The distance by road between population centres is measured. If the distance is less than two kilometres, then the population centres are combined to form a single population centre, provided they do not cross census metropolitan area (CMA) or census agglomeration (CA) boundaries.
5. If a population centre is contained within a census subdivision (CSD) or a designated place (DPL), the difference in land area between the population centre and the CSD or DPL is calculated. For confidentiality purposes, if the difference between the CSD and the population centre is less than 10 square kilometres, then the boundary for the population centre is adjusted to the CSD boundary. However, if the difference between the DPL and the population centre is less than 10 square kilometres and the remaining population is less than 100, then the population centre will annex the entire DPL.

The resulting population centres are reviewed and may be modified to ensure spatial contiguity where appropriate (for example, the removal of interior holes).

Some population centres may contain commercial and industrial districts, railway yards, airports, parks and other uninhabited areas that result in dissemination blocks with population densities of less than 400 persons per square kilometre. In general, the impact on the total population within population centres is minor, but the impact on specific land areas could be significant. This would affect any programs or research based on precise distance or land area measurements related to individual population centres.

Once a population centre attains a population of 10,000 persons, it is eligible to become the core of a census agglomeration (CA). Once a population centre attains a population of 50,000 and is the core of a census agglomeration with a minimum total population of 100,000, then it is eligible to become the core of a census metropolitan area (CMA). When a population centre with a population of at least 50,000 persons is also the core of a census agglomeration, the census agglomeration is eligible for the census tract program.

Naming convention

The name of the population centre is the name of the principal census subdivision (CSD) when the CSD is (or was) a city, town or village. If two or more principal CSDs are involved, the population centre may be given a compound name. In other cases, the name of the population centre is an appropriate place name.

Geographic code

Population centre codes are unique four-digit codes that are assigned sequentially upon the POPCTR creation. These codes remain constant between censuses. The previous 2006 urban area codes are retained for the 2011 population centres. If a population centre is retired due to amalgamation or failure to meet the population or density thresholds, then its code is retired.

It is recommended that the two-digit province/territory (PR) code precede the POPCTR code in order to identify each POPCTR uniquely within its corresponding province/territory. For example:

Five POPCTRs straddle provincial boundaries: Campbellton (New Brunswick and Quebec), Hawkesbury (Ontario and Quebec), Ottawa - Gatineau (Ontario and Quebec), Flin Flon (Manitoba and Saskatchewan) and Lloydminster (Alberta and Saskatchewan).

For 2011, the DPL of Cowichan 1 (DPL 59 0321) in British Columbia overlaps the POPCTR of Duncan (POPCTR 0243). In an effort to minimize data suppression for this area, this DPL represents a formerly discontiguous Aboriginal community which has been combined to form a single discontiguous census subdivision (CSD).

Table 1 in the Introduction shows the number of population centres by province and territory.

Refer to the related definitions of census metropolitan area (CMA) and census agglomeration (CA); census subdivision (CSD); core, fringe and rural area; designated place (DPL); dissemination block (DB); land area; place name (PN) and population density.

Changes prior to the current census:

The term 'urban area' existed at Statistics Canada from the 1961 to 2006 censuses.

For 2006, the boundaries of 412 urban areas for 2001 were adjusted to correct for over-bounding which largely resulted from the 2001 block structure. This correction resulted in the reduction of land area of these 2001 urban areas in preparation for the delineation of the 2006 urban areas. The correction also resulted in the reinstatement of four urban areas for 2006 which had been merged with other urban areas in 2001: Fortune (10 0300), Sainte-Croix (24 0878), Châteauguay (24 1177) and Dowling (35 1084).

One of the 2006 urban areas, Attawaspiskat 91A (UA 35 1275), was an area that had been identified as being an incompletely enumerated Indian reserve. Data for 2006 were not available for the incompletely enumerated reserves and settlements, and were not included in tabulations. Because of the missing data, users were cautioned that for the affected geographic areas, comparisons (e.g., percentage change) between 2001 and 2006 were not exact.

In 2001, the delineation of urban areas became an automated process that made it possible to use population counts and population density data from the current census.

Prior to 2001, the geographic units used for urban area delineation were census subdivisions, designated places and enumeration areas. Population counts and population density from the previous census were used in all cases, except when enumeration area boundaries had been adjusted for the current census.

For 1976, urban areas contained a population concentration of at least 1,000 persons and a population density of at least 1,000 persons per square mile (386 per square kilometre). Urban areas were combined if they were separated by less than one mile (1.6 kilometres).

For 1971, 1966 and 1961, urban areas included:

• all incorporated cities, towns and villages with a population of 1,000 persons or over;
• all unincorporated places with a population of 1,000 persons or over and a population density of at least 1,000 persons per square mile; and
• the urbanized fringe and the urbanized core of a census agglomeration or census metropolitan area, that had a minimum population of 1,000 persons and a density of at least 1,000 persons per square mile.