Dictionary, Census of Population, 2016
Dissemination block (DB)

Release date: November 16, 2016


A dissemination block (DB) is an area bounded on all sides by roads and/or boundaries of standard geographic areas. The dissemination block is the smallest geographic area for which population and dwelling counts are disseminated. Dissemination blocks cover all the territory of Canada.

Reported in

2016, 2011, 2006 (dissemination block)
2001 (block)


Dissemination blocks are primarily an artefact of the road network. As such, the number of DBs created is a function of the timeliness and accuracy of the road network prior to the census. For the 2016 Census, the road network used for DB creation is up to date as of June 2016.

In preparation for the 2016 Census, Statistics Canada developed strategies to ensure dissemination geographies match with topographic datasets used outside Statistics Canada for policy and planning purposes. This convergence work resulted in updates to the current road network and corresponding DB structure. Convergence work was completed in British Columbia, Alberta, Ontario, Quebec, New Brunswick, Nova Scotia and Prince Edward Island.

Highway medians, ramp areas and other irregular polygons may form dissemination blocks on their own. A morphological dissemination block is split to form two or more DBs wherever it is traversed by the boundaries of selected standard geographic areas. This makes it possible to aggregate dissemination block data to all higher level standard geographic areas. In 2011, DB boundaries had to respect the following standard geographic areas: federal electoral districts (FEDs), census subdivisions (CSDs), census tracts (CTs), designated places (DPLs) and dissemination areas (DAs). The 2016 DBs must respect three additional standard geographic areas: namely health regions (HRs), local health integration networks (LHNs) and previous census population centres (POPCTRs).

In rural areas where the road network is sparse or even non-existent, the boundaries of collection blocks are used to avoid creating very large dissemination blocks.

Each dissemination block is assigned a three-digit code. In order to uniquely identify each dissemination block in Canada, the two-digit province/territory (PR) code, the two-digit census division (CD) code and the four-digit dissemination area (DA) code must precede the DB code. For example:

Table - Dissemination block
Table summary
This table displays the results of Table - Dissemination block. The information is grouped by PR-CD-DA-DB code (appearing as row headers), Description (appearing as column headers).
PR-CD-DA-DB code Description
12 09 0103 002 Province 12: Nova Scotia
CD 09: Halifax
DA 0103
DB 002
59 09 0103 003 Province 59: British Columbia
CD 09: Fraser Valley
DA 0103
DB 003

Only population and dwelling counts are disseminated at the dissemination block level (with the dissemination area being the smallest standard geographic area for which characteristic data are disseminated). To ensure confidentiality, population counts are adjusted for dissemination blocks having a population of less than 15.

Table 1.1 in the introduction shows the number of dissemination blocks by province and territory.

Refer to the related definitions of census division (CD); census subdivision (CSD); census tract (CT); designated place (DPL); dissemination area (DA); federal electoral district (FED); population centre (POPCTR) and Spatial Data Infrastructure (SDI).

Changes prior to the current census

In 2006, the term 'dissemination block' replaced the term 'block.'

In 2001, the term 'block' was used.

Prior to 2001, households and their associated population and dwelling counts were geographically referenced to the enumeration area at the time of collection. For more information, refer to the Geography Working Paper Series – Introducing the Dissemination Area for the 2001 Census: An Update (Catalogue no. 92F0138MIE2000004).

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