Geography Working Paper Series
Preliminary 2021 Census Metropolitan Area and Census Agglomeration Delineation

Abstract

This working paper describes the preliminary 2021 census metropolitan areas (CMA) and census agglomerations (CA) and is presented for user feedback. The paper briefly describes the changes to the CMAs and CAs and includes tables and maps that list and illustrate these changes to their limits and to the component census subdivisions. In addition, this paper takes a look at the history of the CMA and CA program and the changes that have occurred since its inception in 1941.

Introduction

The Statistical Geomatics Centre has completed the delineation of the preliminary 2021 census metropolitan areas (CMA) and census agglomerations (CA). This paper summarizes the changes to the CMAs and CAs based on the results of this preliminary delineation for the 2021 Census.

The preliminary 2021 CMA and CA delineation is based on the following:

• interim 2018 census subdivision (CSD)^Note  boundaries – the municipal boundaries as of September 1, 2018;
• final 2016 population centres^Note 
• commuting flows and labour force data from the 2016 Census place of work (POW) variable; and,
• current rules for CMA and CA delineation

Tables and figures included in this paper list the component CSDs for each preliminary 2021 CMA and CA. The tables and figures also show the newly added and removed CSDs. Readers should consult the tables and figures in Appendix 1 for the CMAs or CAs of interest.

Please note that the results presented in this paper are preliminary for the 2021 Census. They are not the final CMA and CA boundaries for the 2021 Census.

Delineation methodology

A census metropolitan area (CMA) or a census agglomeration (CA) is formed by one or more adjacent census subdivisions (CSDs) centred on a population centre (known as the core^Note  ). A CA must have a population centre with at least 10,000 people as its core based on the adjusted counts from the previous Census, while a CMA must have a total population of 100,000 or more where at least 50,000 resides in the population centre core, also based on the adjusted counts from the previous Census.

The preliminary 2021 delineation uses the population centre from the 2016 Census as cores and the CSDs as of September 1^st, 2018 as building blocks. Notably, a CSD re-delineation project was undertaken in the province of Prince Edward Island, resulting in a new CSD structure that is very different from the 2016 Census. To see and download the boundaries of CSDs used by this delineation, please refer to the Census Subdivision Boundary File, 2018^Note  .

It is important to note that although the CSDs used in the preliminary 2021 delineation reflect the boundaries as of September 2018, they contain population counts from the 2016 Census adjusted to these CSD boundaries. These adjusted counts are used to calculate the total population of CMAs and CAs in this preliminary delineation.

To be included in a CMA or CA, a CSD must have a high level of integration with the central core. For the preliminary 2021 delineation, this level of integration is measured by commuting flows derived from the 2016 Census Place of Work (POW) data. These data are the most recent data illustrating the commuting patterns among CSDs. To maintain spatial contiguity, historical comparability, and to take special circumstances into consideration, other CSDs may be added to or retained in a CMA or CA. To determine which CSDs are part of a CMA or CA and to which CMA or CA they belong, they are tested under a set of seven rules, as listed in table 1. For the details of these rules and their application, please refer to the 2016 Census Dictionary on Census metropolitan area (CMA) and census agglomeration (CA)^Note  .

Summary results of the preliminary delineation for the 2021 census metropolitan areas and census agglomerations

The total number of census metropolitan areas (CMAs) and census agglomerations (CAs) remains at 152 from the 2016 Census to the preliminary 2021 Census delineation. The number of CMAs have increased; however, this increase is offset by the decrease in the number of CAs. Table 2 shows the number of CMAs, CAs with census tracts, and CAs without census tracts for 2016 and the preliminary 2021 delineation.

New census metropolitan areas: the promotion of census agglomerations to census metropolitan area status

A CA becomes a CMA as a result of attaining a total population of at least 100,000 of which 50,000 or more live in the core based on the previous Census population counts.

Five CAs are promoted to CMA status in the preliminary 2021 delineation. These promotions increase the number of CMAs from 35 for the 2016 Census to 40 for the preliminary 2021 Census delineation. The new CMAs are displayed in table 3.

New census agglomerations

A new CA is delineated when a population centre outside a CMA or CA attains a population of at least 10,000. There are five new CAs in the preliminary 2021 delineation based on the population counts of population centre from the 2016 Census. Table 4 lists these new CAs.

Retired census agglomerations

A CA is retired from the program if the population of its core is below 10,000. Based on the population counts of the population centre from the 2016 Census, two CAs no longer meet the minimum core population requirement; as a result, they will be retired from the CA program for the 2021 Census. Table 5 shows these retired CAs and their core population centre (POPCTR) population counts.

Merging of adjacent census metropolitan areas and census agglomerations

An existing CA can be merged to an adjacent CMA if the total percentage of commuting interchange between the CA and CMA is at least 35% of the employed labour force living in the CA. Multiple CAs can be merged to the same CMA. When a merge occurs, the core of the CA becomes a secondary core of the CMA to which it is merged.

Three existing CAs are merged with adjacent CMAs in the preliminary 2021 delineation. As indicated in table 6, all three CAs being merged are located in Ontario.

New secondary cores

A secondary core is a population centre with a population of at least 10,000 that is located outside the municipality of the primary core but within the CMA or CA. New secondary cores can arise due to a population centre located within a CMA or CA attaining a population of 10,000 or, as mentioned in the previous section, from the merging of a CA with a CMA. As displayed in table 7, there are 12 new secondary cores in the preliminary 2021 delineation.

New census agglomerations with census tracts: the addition of census agglomerations to the census tract program

CAs with a core population of at least 50,000, as well as all CMAs, are included in the census tract (CT) program. A CT is a small and relatively stable geographic area that usually has a population of less than 10,000^Note  .

According to the 2016 Census population counts, the core of the CA of Saint-Hyacinthe has attained a population of over 50,000; as a result, CTs will be delineated in the CA for the 2021 Census.

Impact on the census tract program

In addition to the CA of Saint-Hyacinthe, CSDs in CAs without CTs merging with CMAs as well as CSDs that are added to CMAs and existing CAs with CTs will also enter the CT program.

In total, 22 CSDs will be added to the CT program. Table 8 shows the breakdown of the number of these CSDs by CMA and CA with CTs. Both Ottawa – Gatineau and Windsor have CSDs being added directly to the CMAs as well as by CAs merging with the CMAs. The remaining CMAs and CAs in the list have CSDs being added directly to them.

Component census subdivisions in the preliminary 2021 census metropolitan area and census agglomeration delineation

Overall, CSDs have been added to or removed from the CMA and CA program in 50 of the 2016 and preliminary 2021 CMAs and CAs. Of these 50 affected CMAs and CAs, 11 are CMAs, 2 are CAs with CTs, and 28 are CAs without CTs. Table 9 shows the number of CSD changes in each affected CMA and CA.

These changes increase the total number of CSDs included within a CMA or CA from 966 for the 2016 Census to 1012 for the preliminary 2021 delineation. Along with the promotion of five CAs with CTs to CMAs, these changes contribute to the changes in the number of CSDs included in each of the three types of CMAs, CAs with CTs, and CAs without CTs between the 2016 Census and the preliminary 2021 delineation, as listed in table 10. The increase in the number of CSDs within CMAs is largely driven by the promotion of five CAs with CTs to CMAs, as these five new CMAs together contain 58 CSDs. Similarly, the decline in the number of CSDs within CAs with CTs is also mostly related to these tracted CA to CMA promotions.

The majority of the CSDs within CMAs and CAs are included due to being part of the delineation core or due to high level of commuting between the delineation core and the CSD. The distribution of CSDs within CMAs and CAs by delineation rules for inclusion are displayed in table 11.

Overall, a higher percentage of CSDs are included in CMAs and CAs because they have strong commuting with the cores, as evident by the increased proportions of CSD under rules 2, 3, and 4. The increase of CSDs under rule 7 indicates growth in the number of secondary cores as well as the strengthening commuting relationships between secondary cores and their adjacent primary cores of CMAs.

The increases of percentage of CSDs being included under rules 2, 3, 4, and 7 are offset by decreases in the percentage of CSDs included under rules 1 and 6.

Please refer to the tables in Appendix 1 for the changes in CSD compositions and delineation rules for each CMA and CA.

Census subdivisions added to census metropolitan areas and census agglomerations

A total of 86 CSDs are newly added to CMAs and CAs in the preliminary 2021 delineation: 12 CSDs added to CMAs, one CSD added to CAs with CTs, and 73 CSDs added to CAs without CTs.

Of the 86 CSDs added, 12 are added under the delineation core rule, 51 are added under the forward commuting flow rule, one is added under the reverse commuting flow rule, nine are added under the spatial contiguity rule, and 13 are added under the manual adjustments rule.

The provinces of British Columbia, Quebec, and Prince Edward Island have the highest number of CSD additions to CMAs and CAs, with 26, 25, and 18 CSDs being added respectively. Both British Columbia and Quebec have two new CAs which account for about half of the CSDs being added in both provinces.

Seventeen of the 18 CSDs being added in Prince Edward Island are new CSDs that are the results of a CSD re-delineation project completed by Statistics Canada with the province as of September 2018. These CSD additions therefore do not reflect only component CSDs being added to the existing boundaries of the CAs in Prince Edward Island, but also the changes of the CSD structure within the existing CA boundaries.

All except one of the CSDs added to CMAs are included under the forward commuting flow rule. The one exception is included under the spatial contiguity rule. Table 12 lists all CSDs that are added to CMAs and the rule under which each CSD is included.

Table 13 shows the only CSD that is added to CAs with CTs. The CSD is included under the forward commuting flow rule.

Of the 73 CSDs added to CAs without CTs, 12 are included under the delineation core rule, 39 are included under the forward commuting flow rule, one is included under the reverse commuting flow rule, eight are included under the spatial contiguity rule, and 13 are included under the manual adjustments rule. Table 14 lists all CSDs that are added to CAs without CTs and the rule under which each CSD is included.

Census subdivisions removed from census agglomerations

A total of 34 CSDs are removed from 17 preliminary 2021 CAs. Eighteen CSDs are removed because they no longer meet any of the delineation criteria, and the other 16 CSDs are removed because they have been dissolved or become inactive since the 2016 Census. Four of these CSDs are in New Brunswick. The rest are in Prince Edward Island; these are related to the CSD re-delineation project in the province. Table 15 shows all CSDs that are removed from CAs.

Six CSDs are removed from the CA program due to the retirement of the two CAs to which they belong. These CSDs are displayed in table 16.

Release date and more information of the final 2021 delineation

The final census metropolitan area (CMA) and census agglomeration (CA) boundaries for the 2021 Census will be delineated in 2021 using the population centres from the 2016 Census and the final census subdivision (CSD) boundaries for the 2021 Census. As a result, the final CMAs and CAs will reflect the cumulative CSD changes occurring between January 2, 2016 and January 1, 2021.

All population counts and Place of Work data used to delineate the final 2021 CMAs and CAs will be from the 2016 Census, adjusted to the final 2021 CSD boundaries.

The final 2021 CMA and CA delineation may also include user feedback from the preliminary 2021 CMA and CA delineation working paper.

The boundaries for the final 2021 CMAs and CAs are expected to be released in the fall of 2021.

History of the concept and criteria of census metropolitan area and census agglomeration delineation (1941 to 2021) ^Note 

The census metropolitan areas (CMA) and census agglomerations (CA) concept has existed since the 1941 Census. Over the years, the name of the entities and the methodology used to derive these entities have evolved. This section looks back at the changes that have taken place since the inception of the CMA and CA program.

1941

Statistics Canada published data on ‘greater cities’ for the first time. These were defined as cities which have well-defined satellite communities in close economic relationship with them.

1946

No changes were made.

1951

The term ‘census metropolitan area’ (CMA) 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 of today’s ‘census agglomeration’ (CA), 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.

1956

No changes were made.

1961

CMAs were delineated around cities with a population of at least 50,000 if the following criteria were met: population density of the urbanized area was at least 1,000 persons per square mile (386 people per square kilometre); a labour force outside the central city of which at least 70% were engaged in non-agricultural activities; and the total CMA population was at least 100,000.

1966

No changes were made.

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 around an urbanized core with at least 100,000 population and a density of at least 1,000 persons per square mile. Municipalities within a 20-mile radius of the urbanized core were included in the CMA if the percentage of their labour force in primary activities was smaller than the national average and the percentage of population increase for 1956-1966 was larger than the average for the 1966 CMA. Where only one of the two preceding criteria was met, municipalities were included if they were accessed by a provincial or federal highway.

The term ‘census agglomeration’ (CA) appeared for the first time, replacing ‘major urban areas’. 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.

1976

Commuting data based on the place of work question of the previous decennial census were used for the first time to delineate CMAs. Municipalities were included in CMAs if they met the forward commuting threshold of 40% or the reverse commuting threshold of 25% with the urbanized core.

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 census subdivision (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.

1986

Introduction of the consolidated and primary CMA and CA concept. Adjacent CMAs and CAs that had sufficient commuting interchange (35% or more) were merged and 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.

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.

1991

No changes were made.

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.

2001

CAs were required to have an urban core population of at least 100,000 to be changed to the status of a CMA.

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.

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.

2011

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.

2016

Commuting data based on the place of work question from the 2011 National Household Survey were used for CMA and CA delineation. However, data in the category of no fixed workplace address were excluded from the commuting flow calculations.

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 one more census. This change means that these CSDs could be removed from CMAs and CAs after the next census or the next delineation.

2021

No changes were made.

History of entries and deletes of 2016 and preliminary 2021 census metropolitan areas and census agglomerations

References

Dubuisson, R. 1983. “Metropolitan area concepts in Canada and selected foreign countries.” Statistics Canada Catalogue no. 92-X-503.

Ricour-Singh, F. 1972. “1971 census agglomerations delineation and general characteristics.”

Ricour-Singh, F. 1972. “Census metropolitan areas: revision of the concept, criteria and delineations for the 1971 Census.”

Ross, G. 1984. “Census metropolitan area/census agglomeration program, a review, 1941-1981.” Statistics Canada Catalogue no. 92-X-508.

Acknowledgements

This working paper is the culmination of the work of several individuals in the Statistical Geomatics Centre. The dedicated work of Michel Carleton, Luc Therrien, Mary-Ellen Maybee, Brigit Levac, Kaily Barry, Sophie Gratton, Kelly Matier and Geneviève Clément are acknowledged.

Appendices

Maps and tables for each preliminary 2021 census metropolitan area and census agglomeration

Additional information