Dictionary, Census of Population, 2021
Census metropolitan area (CMA) and census agglomeration (CA)

Definition

A census metropolitan area (CMA) or a census agglomeration (CA) is formed by one or more adjacent municipalities centred on a population centre (known as the core). A CMA must have a total population of at least 100,000, based on data from the current Census of Population Program, of which 50,000 or more must live in the core based on adjusted data from the previous Census of Population Program. A CA must have a core population of at least 10,000 also based on data from the previous Census of Population Program. To be included in the CMA or CA, other adjacent municipalities must have a high degree of integration with the core, as measured by commuting flows derived from data on place of work from the previous Census Program.

If the population of the core of a CA falls below 10,000, the CA is retired from the next census. However, once an area becomes a CMA, it is retained as a CMA even if its total population declines below 100,000 or the population of its core falls below 50,000. All areas inside the CMA or CA that are not population centres are rural areas.

When a CA has a core of at least 50,000, based on data from the previous Census of Population, it is subdivided into census tracts. Census tracts are maintained for the CA even if the population of the core subsequently falls below 50,000. All CMAs are subdivided into census tracts.

Reported in

2021, 2016, 2011, 2006, 2001, 1996, 1991, 1986, 1981, 1976, 1971, 1966, 1961, 1956, 1951 and 1941

Remarks

The terms 'population centre,' 'core,' 'fringe' and 'rural area' replace the terms 'urban area,' 'urban core,' 'urban fringe' and 'rural fringe' since the 2011 Census.

The type of population centre is determined by the relationship between the population centre and the structure of the census metropolitan areas (CMAs) or census agglomerations (CAs). Possible types within a CMA or CA are as follows: core, secondary core, fringe and rural area.

Cores

A census metropolitan area (CMA) or a census agglomeration (CA) can have more than one core. The boundaries and population data for the cores that are used to delineate CMAs and CAs are taken from the previous census. Moreover, the core of a CMA must have a population of at least 50,000 and the core of a CA must have a population of at least 10,000. In all other cases where a CMA or a CA has more than one core, the additional cores are called fringes if they are in the same municipality (census subdivision), or secondary cores if they are in another municipality. In both cases, the population exceeds 10,000. If the previous census population count of a population centre does not exceed 10,000, it is also called a fringe. Also, when a CA is merged with a CMA, the core of the former CA also becomes a secondary core of that CMA. If the population of a fringe exceeds 10,000, and it is not in the same municipality as an existing core, it becomes a secondary core of the CMA or CA in which it exists.

Delineation rules for CMAs and CAs

A CMA or CA is delineated using adjacent municipalities (census subdivisions) as building blocks. These census subdivisions (CSDs) are included in the CMA or CA if they meet at least one of the following rules. The rules are ranked in order of priority. A CSD obeying the rules for two or more CMAs or CAs is included in the one for which it has the highest ranked rule. If the CSD meets rules that have the same rank, the decision is based on the population or the number of commuters (journey to work) involved. A CMA or CA is delineated to ensure spatial contiguity.

1. Delineation core rule: The CSD falls completely or partly (at least 50% of its population) inside the core.

For the purposes of CMA and CA delineation, a delineation core composed of one or more CSDs is created. For a CSD to be included in the primary or secondary delineation core, at least 50% of its population must reside in the core. In Figure 1.6, CSD A is part of the delineation core since its entire population resides in the core. CSD B is also part of the delineation core because at least 50% of its population resides in the core. The core hole, i.e., CSD K, is not considered to be included in the delineation core and will therefore be available for other delineation rules described below.

2. Forward commuting flow rule: Given a minimum of 100 commuters, at least 50% of the employed labour force living in the CSD works in the delineation core, as determined by the previous rule. See the addition of the CSD C in the Figure 1.7. These counts are established based on responses to the place of work question from the previous Census Program (see note below).

Note: To delineate the CMAs and CAs, the data on place of work are taken from the Census Program. Commuting, i.e., the journey to work, comprises four categories: at home; outside Canada; no fixed workplace address and usual place of work. The calculation of the employed labour force excludes the category of no fixed workplace address. Moreover, all calculations of commuting flows exclude data on no fixed workplace address.

3. Reverse commuting flow rule: Given a minimum of 100 commuters, at least 50%* of the employed labour force working in the CSD lives in the delineation core as determined from commuting data based on the place of work question from the previous Census Program. In Figure 1.8, at least 50%* of the employed labour force working in CSD D lives in the CSDs A and B (see note for rule 2).

* Prior to 2016, the percentage was set at 25%.

4. Spatial contiguity rule: Where necessary to eliminate holes, CSDs that do not meet a commuting flow threshold may be included in a CMA or CA, and CSDs that do meet a commuting flow threshold may be excluded from a CMA or CA.

Two situations can lead to the inclusion or exclusion of a CSD in a CMA or CA for reasons of spatial contiguity. Specifically, these are:

Outlier – A CSD (E in Figure 1.9) with sufficient commuting flows (either forward or reverse) is enclosed by a CSD (F in Figure 1.9) with insufficient commuting flows, but which is adjacent to the CMA or CA. When this situation arises, the CSDs within and including the enclosing CSD are grouped to create a minimum CSD set (E + F). The total commuting flows for the minimum CSD set are then considered for inclusion in the CMA or CA. If the minimum CSD set has sufficient commuting flows (either forward or reverse) and the total minimum of commuters is at least 100, then all of its CSDs are included in the CMA or CA.

Hole – A CSD (G in Figure 1.9) with insufficient commuting flows (either forward or reverse) is enclosed by a CSD (H in Figure 1.9) with sufficient commuting flows, and which is adjacent to the CMA or CA. When this situation arises, the CSDs within and including the enclosing CSD are grouped to create a minimum CSD set (G + H). The total commuting flows for the minimum CSD set are then considered for inclusion in the CMA or CA. If the minimum CSD set has sufficient commuting flows (either forward or reverse) and the total minimum of commuters is at least 100, then all of its CSDs are included in the CMA or CA.

5. Historical comparability rule: To maintain historical comparability for CMAs and larger CAs (those with census tracts in the previous census), CSDs are retained in the CMA or CA under this rule for at least one census even if their commuting fall below the minimum commuting flow thresholds (rules 2, 3 or 4). Users should be forewarned that a CSD can be excluded from a CMA or from a larger CA in the next census or the next delineation. See Figure 1.10 for the addition of the CSD I.

An exception to the historical comparability rule is made in cases where CSDs have undergone changes to their boundaries, such as annexations. To determine whether to keep or exclude a CSD, place of work data are re-tabulated for the CSD with boundary changes, and a decision to include or exclude the CSD is made according to the previous rules.

6. Manual adjustments: A CMA or CA represents an area that is economically and socially integrated. However, there are certain limitations in the extent to which this ideal can be met. Since the CSDs that are used as building blocks in CMA and CA delineation are administrative units, their boundaries do not always match other statistical units (i.e., population centre cores). There can be situations where the application of the above rules creates undesirable outcomes, or where the rules cannot be easily applied. In these circumstances, a manual override is sometimes applied to ensure that the integrity of the program is retained.

One example is when the CSD is partially inside the core and, based on data from the previous Census of Population, less than 50% of its population resides in the core. Furthermore, the CSD does not meet any of the other delineation rules (rules 1, 2, 3 or 4), so it is included in the CMA or CA with manual adjustments. In Figure 1.16, CSDs A and B are included in the CMA under the delineation core rule, while CSD J is retained under the manual adjustment rule (core).

Another example of manual adjustment is a core hole, which refers to a CSD that does not qualify for any delineation rule (rules 1, 2, 3 or 4) but is located inside another CSD that does qualify under the delineation core rule (rule 1). In these situations, core holes are included in the CMA or CA to maintain spatial contiguity. In Figure 1.16, CSDs A and B are included in the CMA under the delineation core rule, while CSD K is retained under the manual adjustment rule (core hole).

Thus, in Figure 1.16, CSDs A and B are included in the CMA under the delineation core rule, while CSDs J and K are both part of the manual adjustment rule, specifically under the core and core hole criteria respectively.

Finally, the CSDs that are completely surrounded by other CSDs that are already included in a CMA or CA, that consist of several parts or that contain holes also influence the application of the manual adjustment rule. An example of this situation can be found in Miramichi CA (New Brunswick), where the CSD of Red Bank 4, IRI, which is surrounded by other CSDs that are already included in the CA and is in two parts, is included to maintain spatial contiguity. See CSD L, in two parts, of which one is surrounded by other CSDs that are already included in the CMA, in Figure 1.16.

7. Merging adjacent CMAs and CAs and secondary core rule: A CA adjacent to a CMA can be merged with the CMA if the total percentage commuting (journey to work) interchange between the CA and CMA is equal to at least 35% of the employed labour force living in the CA, based on place of work data from the previous Census Program. The total percentage commuting interchange is the sum of the commuting flow in both directions between the CMA and the CA as a percentage of the labour force living in the CA (i.e., resident employed labour force, excluding the no fixed workplace address category).

If more than one CA is adjacent to the same CMA, each CA is assessed separately with the CMA. Several CAs may be merged with one CMA. If the total percentage commuting interchange is less than 35%, the CMA and CA are not merged. After a CA is merged with a CMA, the core of the former CA is called the secondary core of the CMA. See Figure 1.11.

Naming convention for CMAs and CAs

The convention for the naming of a CMA or CA is based on the name of the principal population centre or largest municipality at the time the CMA or CA was first formed. This standard had been used since the 1971 Census. Through the years, the CMA and CA names have remained stable. The most important changes resulted from name changes to the census subdivisions (resulting from municipal dissolutions, incorporations and name changes).

Guidelines for CMA name change requests

The key revision to the convention is the establishment of 'Guidelines for CMA name change requests' as published in Preliminary 2011 Census Metropolitan and Census Agglomeration Delineation (Catalogue no. 92F0138M). Below are the guidelines for requesting a change:

1. CMA names can consist of up to three legislated municipal names of eligible census subdivisions (CSDs) that are components of the CMA. However, the number of name elements in any new CMA name request is limited to five. If any of the eligible CSD names are already hyphenated or compound, the number of CSD names will be limited to two or one if the number of name elements exceeds five.
2. The eligible municipal names include the historic central municipality name and the two component CSDs with the largest population, and having a population of at least 10,000, according to the last census.
3. The ordering of the municipal names within the CMA name is determined by the historic (central) municipality and the population size of the eligible CSDs. The first component of the CMA name is always the historic (central) CSD even if its census population count is less than the other eligible component CSDs. This ensures that CMA names retain a measure of stability for better longitudinal recognition. The second and third place name order is determined by population size. The component CSD with the higher census population count at the time of the name change assumes the second position and the next largest component CSD, the third position.
4. In order for a requested CMA name change to be implemented, there must be explicit consensus among all eligible component municipalities on a proposed new name and a formal request, in accordance with these guidelines, must be sent to the Director of the Statistical Geomatics Centre at Statistics Canada by June 1 of the year prior to the census. The CMA name change will be implemented in the revision of the Standard Geographical Classification related to the census under consideration.
5. Statistics Canada will continue to change CMA names whenever the legislated name of a municipality changes. Any other request for a name change will only be considered within the context of these guidelines.

CMA/CA coding structure

Each CMA and CA is assigned a three‑digit code that identifies it uniquely in Canada. The first digit is the same as the second digit of the province code in which the CMA or CA is located. If a CMA or CA spans a provincial boundary, then the province code assigned represents the province with the greater proportion of core population. Codes for CAs in Yukon and the Northwest Territories begin with the same digit as for those CMAs or CAs located in British Columbia. There are currently no CMAs or CAs in Nunavut.

If data for provincial parts are required, it is recommended that the two‑digit province/territory (PR) code precede the CMA/CA code for those CMAs/CAs that cross provincial boundaries. For example:

Table 1.1 shows the number of census metropolitan areas and census agglomerations by province and territory.

Changes to the name and number of CMAs and CAs for the 2021 Census

One CMA from the previous census changed its name: Belleville became Belleville - Quinte West.

Some CAs may change type between censuses. For the 2021 Census, Fredericton (N.B.), Drummondville (Que.), Red Deer (Alta.), Kamloops (B.C.), Chilliwack (B.C.) and Nanaimo (B.C.), which were all CAs in 2016, became CMAs, while Saint‑Hyacinthe (Que.) is now subdivided into census tracts because its core population was at least 50,000 in the previous census.

Five new CAs were created: Sainte‑Agathe‑des‑Monts (Que.), Amos (Que.), Essa (Ont.), Trail (B.C.) and Ladysmith (B.C.). The names of all these new CAs were based on the largest municipality (census subdivisions).

The CAs of Bay Roberts (N.L.), and Cold Lake (Alta.) were retired because the population of their cores dropped below 10,000 in 2016.

Data quality

CMAs and CAs are statistically comparable because they are delineated in the same way across Canada. They differ from other areas such as trading or marketing areas, or regional planning areas designated by regional authorities for planning and other purposes, and should be used with caution for non‑statistical purposes.

The CSD limits used in CMA and CA delineation are those in effect on January 1, 2021 (the geographic reference date for the 2021 Census). In addition, CMA and CA delineation uses commuting (journey to work) data based on the place of work question asked in the previous Census Program.

Refer to the related definitions of Population Centre (POPCTR); Core, Fringe and Rural Area and Census Subdivision (CSD).

Changes prior to the current census

2016

• Prior to the 2021 Census, CMA delineation used the total population counts from the previous census to determine the type change from CA to CMA.
• Two CAs became CMAs: Belleville (Ont.) and Lethbridge (Alta.).
• Two CAs were subdivided into census tracts: Grande Prairie (Alta.) and Wood Buffalo (Alta.).
• Eight new CAs were created: Gander (N.L.), Sainte‑Marie (Que.), Arnprior (Ont.), Carleton Place (Ont.), Wasaga Beach (Ont.), Winkler (Man.), Weyburn (Sask.) and Nelson (B.C.).
• The CAs of Amos (Que.), and Temiskaming Shores (Ont.) were retired because their respective core populations dropped below 10,000 in 2011.
• CMA and CA delineation used commuting data based on the place of work question from the 2011 National Household Survey. However, employed labour force and commuting flow calculations started excluding data in the category of no fixed workplace address.
• For both CMAs and CAs, the forward commuting threshold remained at 50%, while the reverse commuting threshold was raised from 25% to 50%.
• CSDs in CMAs and CAs with census tracts that were included under the historical comparability rule would be retained for at least one census. This change means that these CSDs could be removed from CMAs and CAs after the next census or delineation.

2011

• In 2011, the CMA of Abbotsford became Abbotsford-Mission (B.C.) and the CMA of Kitchener became Kitchener-Cambridge-Waterloo (Ont.).
• Five new CAs were created: Steinbach (Man.), High River (Alta.), Strathmore (Alta.), Sylvan Lake (Alta.) and Lacombe (Alta.).
• The CAs of La Tuque (Que.) and Kitimat (B.C.) were retired because the population of their cores dropped below 10,000 in 2006.
• The terms 'population centre,' 'core,' 'fringe' and 'rural area' replace the terms 'urban area,' 'urban core,' 'urban fringe' and 'rural fringe' for the 2011 Census.
• CMA and CA delineation started using commuting data based on the place of work question asked in the most recent census instead of the previous decennial census.
• The 'Guidelines for CMA name change requests' were established to allow municipalities to submit formal requests of new names for CMAs.

2006

• For 2006, CAs were no longer required to have an urban core population of 100,000 to be promoted to the status of a CMA. Instead, CAs assumed the status of a CMA if they had attained a total population of at least 100,000 of which 50,000 or more lived in the urban core.
• Prior to the 2011 Census, CMA and CA delineation used commuting data based on the place of work question asked in the decennial census. The 2006 CMAs and CAs are based on the population and place of work data from the 2001 Census while the 2001 and 1996 CMAs and CAs are based on population and place of work data from the 1991 Census.

2001

• For 2001, CAs were required to have an urban core population of at least 100,000 to be changed to the status of a CMA.
• For 2001, consolidated CMAs were no longer defined for dissemination purposes. As a result, primary CMAs and primary CAs were also not defined. However, the consolidation rule was retained and incorporated into the CMA delineation methodology. There was no substantive change to the methodology for defining CMAs and no change to the limits of CMAs resulting from this rule change.
• Prior to 2001, adjacent CMAs and CAs that had sufficient commuting interchange (35% or more) and were merged were identified by the terms 'primary census metropolitan area (PCMA)' and 'primary census agglomeration (PCA).' The terms 'consolidated census metropolitan area (CCMA)' and 'consolidated census agglomeration (CCA)' described the sum of the component CMAs and CAs. Census data were disseminated for these areas. These terms were not used for the standard dissemination program for 2001.
• Six of 27 CMAs were affected significantly as a result of municipal restructuring: Halifax (N.S.), Ottawa - Hull (Ont./Que.), Kingston (Ont.), Greater Sudbury (Ont.), London (Ont.) and Windsor (Ont.).

1996

• Two changes to CMA/CA delineation rules were implemented to preserve data comparability over time. CMAs could be consolidated with CAs, but they could not be consolidated with other CMAs. A primary census agglomeration (PCA) could not be retired from a consolidated CMA or CA (with census tracts at the previous census) even if its total commuting interchange percentage dropped below the consolidation threshold of 35%. Exceptions to this rule could occur due to changes in the physical structure of the urban areas used to determine the urban cores.
• Minimum sets of CSDs were used instead of the census consolidated subdivisions (CCSs) for evaluation in the spatial contiguity rule. Refer to the spatial contiguity rule (rule 4).

1986

• Introduction of the consolidated and primary CMA and CA concept.
• The forward commuting threshold was raised from 40% to 50% to control for differences in processing of the place of work data between 1971 and 1981.
• Introduction of the minimum of 100 commuters for forward and reverse commuting for both CMAs and CAs. Single CSD (component) CAs were permitted.

1981

• Commuting data based on the place of work question of the previous decennial census were used for the first time to delineate CAs. For both CMAs and CAs, the forward commuting threshold was 40% and the reverse commuting threshold was 25%.
• The minimum urbanized core population for CAs was raised from 2,000 to 10,000.
• CAs were eligible for census tracts if they had a CSD with a population of at least 50,000 at the time of the previous census. Single CSD (component) CAs could be created for subdivision into census tracts.

1976

• Commuting data based on the place of work question of the previous decennial census were used for the first time to delineate CMAs. The forward commuting threshold was 40% and the reverse commuting threshold was 25% for the CMAs.
• For CAs, see 1971.

1971

• CMAs were defined as main labour market areas, but were delineated according to alternate criteria based on the labour force composition, population growth rate and accessibility. At this time, the CMA of Saint John, N.B. was 'grandfathered.'
• CAs were comprised of at least two adjacent municipal entities. These entities had to be at least partly urban and belong to an urbanized core having a population of at least 2,000. The urbanized core included a largest city and a remainder, each with a population of at least 1,000, and had a population density of at least 1,000 per square mile (386 people per square kilometre).

1966

• See 1961.

1961

• CMAs were delineated around cities with a population of at least 50,000, if the population density and labour force composition criteria were met, and the total CMA population was at least 100,000.
• CAs were called major urban areas; see 1951.

1956

• See 1951.

1951

• The term 'census metropolitan area' appeared for the first time. This term designated cities of over 50,000 having fringe municipalities in close geographic, economic and social relations, the whole constituting a unit of over 100,000.
• The concept of 'major urban areas,' the forerunners to CAs, was introduced. The term designated urban areas in which the largest city had a population of at least 25,000 and fewer than 50,000.

1941

• Data were published for 'greater cities,' i.e., those cities which have well‑defined satellite communities in close economic relationship to them.