Dictionary, Census of Population, 2021
Census tract (CT)

Definition

Census tracts (CTs) are small, relatively stable geographic areas that usually have a population of fewer than 7,500 persons, based on data from the previous Census of Population Program. They are located in census metropolitan areas (CMAs) and in census agglomerations (CAs) that had a core population of 50,000 or more in the previous census.

A committee of local specialists (for example, municipal planners and others) initially delineates CTs in conjunction with Statistics Canada. Once a CMA or CA has been subdivided into CTs, the CTs are maintained even if the core population subsequently declines below 50,000.

Reported in

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

Remarks

Rules are used to delineate census tracts (CTs). The initial delineation rules are ranked in the order of the following priorities:

1. CT boundaries must follow permanent and easily recognizable physical features. However, street extensions, utility or transportation easements, property lines and former municipal limits may be used as CT boundaries if physical features are not in close proximity or do not exist.
2. Starting with the 2016 Census, CT boundaries must follow the boundaries of the census subdivision (CSD) types associated with the on‑reserve population.
3. The population of a CT usually ranges between 2,500 and 7,500, with a preferred average of 5,000. CTs on reserves, in the central business district, in major commercial and industrial zones, or in peripheral areas can have populations outside this range.
4. CTs should be as homogeneous as possible in terms of socioeconomic characteristics, such as similar economic status and social living conditions, at the time of their creation.
5. The shape of CTs should be as compact as possible.
6. CT boundaries respect aggregate dissemination area, census metropolitan area (CMA), census agglomeration (CA) and provincial boundaries, but do not necessarily respect CSD (municipality) boundaries.

Changes to CT boundaries are discouraged to ensure data comparability between censuses. Boundary revisions occur only when they are essential. Road construction, railroad abandonment, community redevelopment, neighbourhood growth and municipal annexations may contribute to changes in boundaries, often with input from local specialists. A CT may be split into two or more new CTs (usually when its population exceeds 7,500. CT splits are usually done in a way that allows users to re‑aggregate the splits to the original CT for historical comparison.

Naming convention for census tracts

Each CT is assigned a seven‑character numeric "name" (including leading zeros, decimal point and trailing zeros). To uniquely identify each CT in its corresponding CMA or tracted CA, the three‑digit CMA or CA code must precede the CT name. For example:

CT naming is consistent from census to census to facilitate historical comparability.

When a CA enters the CT program, the CSD that gives the CA its name is assigned the first CT name, starting at 0001.00. When all of the CTs in the first CSD are named, then the CTs of the adjoining CSDs are named, and finally those on the periphery.

If a CT is split into two or more parts because of population increase, the number after the decimal point identifies the splits. For example, CT 0042.00 becomes CT 0042.01 and CT 0042.02. If CT 0042.01 is subsequently split, it becomes CT 0042.03 and CT 0042.04. Similarly, if CT 0042.02 is split after CT 0042.01, it becomes CT 0042.05 and CT 0042.06. Any splits occurring after this would be numbered in a similar way, with the next sequential number. This allows users to re-aggregate the splits to the original CT.

Table 1.1 shows the number of CTs by province and territory.

The nature of the CT concept, along with the availability of a wide range of census data, makes CTs useful in many applications. These include

• municipal and regional planning and research, such as the development, evaluation and revision of official plans
• educational and research studies in high schools, community colleges and universities
• market research, such as to identify areas of opportunity and evaluate market or service potential for housing, health, educational, recreational or retailing facilities.

CTs should be used with caution for non‑statistical purposes.

Refer to the related definition of Census Metropolitan Area (CMA) and Census Agglomeration (CA).

Changes prior to the current census

Beginning in 2016, census tract boundaries must follow the boundaries of the census subdivision types associated with the on‑reserve population. This change aligned census tracts to the definition of aggregate dissemination areas, where all census subdivision types associated with the on-reserve population form their own aggregate dissemination areas, and census tracts must respect aggregate dissemination area boundaries.

Refer to the related definition of Aggregate Dissemination Area (ADA).

Beginning in 1996, census agglomerations were eligible for census tracts based on the population size of their cores (50,000 or more in the previous census). This was a change from previous censuses, when census agglomerations had to contain a municipality (census subdivision) with a population of 50,000 or more in the previous census to be eligible for census tracts.

From 1971 to 1991, a provincial census tract program existed. Provincial census tracts were similar in concept to census tracts, but covered areas outside census metropolitan areas and census agglomerations. Taken together, census tracts and provincial census tracts covered all of Canada.

In 1941 and 1946, census tracts were called "social areas."