Municipal identification codes in Ontario

DGUID

Dissemination Geography Unique Identifier – DGUID is an alphanumeric code, composed of four components. It varies from 10 to 20 characters in length. The first 9 characters are fixed in composition and length.

• Vintage (4) + Type (1) + Schema (4) + Geographic Unique Identifier (2-11) :
• VVVV T SSSS GGGGGGGGGGG
• Vintage is a four digit code (e.g., 2021) indicating the reference year of the geospatial data.
• Type is a one character code (e.g., A) indicating the type of geographic areas. At this time there are five geographic area types:
  • A Administrative areas
  • S Statistical areas
  • C Combined areas
  • B Blended areas
  • Z Other
• Schema is a four digit sequential number (e.g., 0005) assigned to each unique geographic area defined by type.
• Geographic Unique Identifier is a variable length alpha‑numeric code (e.g., 3520005) assigned to each individual geographic area. For more detail see the Geographic Code definition. The Geographic Unique Identifiers range from 1 to 12 characters in length.

• CDUID – 4 character ID that uniquely identifies a census division (composed of the 2-digit province or territory unique identifier followed by the 2-digit census division code).
• CCSUID – 7 character ID that uniquely identifies a census consolidated subdivision (composed of the 2-digit province or territory unique identifier followed by the 2-digit census division code and the 3-digit census consolidated subdivision code).
• CSDUID – 7 character ID that uniquely identifies a census subdivision (composed of the 2-digit province or territory unique identifier followed by the 2-digit census division code and the 3-digit census subdivision code) in the 2017 Census Subdivision Boundary File.

ALT_GEO_CODE

alternate geographic code that is usually equal to the ending digits of the DGUID and is often the geographic code found in previous census cycle products.

SGC Code

Standard Geographical Classification (SGC) is Statistics Canada’s official classification for geographic areas in Canada, including all:

• geographical regions of Canada
• provinces and territories, census divisions (counties, regional county municipalities)
• census subdivisions (municipalities)

The names and codes for census metropolitan areas, census agglomerations, census metropolitan influenced zones, economic regions, North and South, census agricultural regions and census consolidated subdivisions are shown as the variants of SGC 2021.

The Standard Geographical Classification (SGC) is a system of names and codes representing areas of Canada.

It consists of a three-tiered hierarchy – province or territory, census division, and census subdivision. Lower levels of Census geography such as Census Tracts (CTs), Enumeration Areas (EAs) prior to 1996, and Dissemination Areas (DAs) from 2001 onward, are less commonly used for collection of health data but can be used for analysis based on recoding from the postal codes (see later discussion of postal code system). CTs, EAs and DAs are available for Census data 2 and can be useful for regrouping into some level of geography lower than the CSD level for “community level” analysis. Most data produced by Statistics Canada uses this system including Census data, population estimates and projections.

Each geographic area receives a unique numeric code ranging from 1 to 7 digits in 1 to 4 parts (XX YY ZZZ):

• XX: Code which identifies the Region, County, or District where the municipality is located.
• YY: Code which identifies the Municipalities status according to the following table:
• ZZ: Represent a sequential ordering of Municipalities of the same status in the same Geographic region, county, or district.

Example

• 35 represents Ontario
• 18 represents Durham Region
• 013 represents the City of Oshawa

More: Standard Geographical Classification (SGC) 2021

MAH Code

Municipal Affairs and Housing Code (MAH Code) which is associated with the municipality (also known as TEIGA (Treasury Economics
and Inter-Governmental Affairs) code). The code is unique over time. That is, even through status changes and new municipalities come into being as a result of amalgamations, previously used codes are retired, and never re-used. This code is used for structured sorts. It must be unique
within the Ministry of Municipal Affairs and Housings Municipal Analysis and Retrieval System (MARS) database. Because this code changes when the status of the municipality changes, it is not used as a unique identifier. This code is carried as a historical reference and to link to older
data systems.

The MAH Code is a five-digit code which is unique to each municipality in the province. The five-digit MAH Code is divided into three parts (XXYZZ):

• First 2 digits (XX): Code which identifies the Region, County, or District where the municipality is located.
• 3rd digit (Y): Code which identifies the Municipalities status according to the following table:
• Last 2 digits (ZZ): Represent a sequential ordering of Municipalities of the same status in the same Geographic region, county, or district.

3rd digit

Example

27401 Town of Aurora (in York Region)

• 27 Represents York Region
• 4 Represents Town
• 01 Identifies Aurora as Town 1 in the Region

Municipal Assessment Code

Municipal Assessment Code (ASMT Code) which is a four-digit code which is unique to each municipality in the province used by the Municipal Property Assessment Corporation (MPAC) to identify properties in the assessment roll.

A municipal code provided by the Municipal Property and Assessment Corporation (MPAC) (formerly Ministry of Revenue). It is also known as the Revenue Code. The four-digit code made up of two portions: the first two digits describe the geographic Upper Tier in which the municipality is located, the second pair of digits uniquely describe the Lower Tier Municipality within the geographic Upper Tier.

Since MPAC maintains assessment data only at the Lower Tier level, this code has been made-up for Upper Tier Municipalities in the Municipal Analysis and Retrieval System (MARS) data base. The code in MARS also had to be made-up for the new City of Toronto after the 1998 amalgamation, since MPAC continued to carry the codes of the former municipalities.

The first 4 digits of properties roll number begins with this code. It is split into 2 parts (XXYY):

• First 2 digits: Identifies the Region, County, or District where the municipality is located.
• Last 2 digits: Identifies each Municipality

Example

1946 Town of Aurora (in York Region)

• 19 Represents York R
• 46 Represents Aurora T

MSO Code

MSO Code is a 2 digit code to identify the Municipal Service Office.

MOHLTC Residence Coding System

The Ontario Ministry of Health and Long Term Care (MOHLTC) bases all geography on the MOHLTC Residence Coding System. The lowest level (4 digits) represents municipalities, townships, named settlements, First Nations Reservations, and unorganized areas. These geographic units are the basis of the Public Health Unit geography. Most data coming from Statistics Canada, including population estimates and projections and vital statistics must be regrouped into Residence Codes based on Census Sub Division (CSD). Because some CSDs map to more than one Residence Code, decisions regarding the assignment of CSDs to unique Residence Codes are made by the MOHLTC. Residence Codes reflect changes in the municipal boundaries that occur between Census years whereas Statistics Canada’s data is based on CSDs from the most recent Census.

The next highest level of geography for MOHLTC is the county/district. Counties are created by grouping 4-digit Residence Codes together and therefore differ somewhat from Statistics Canada’s Census Divisions (based on groupings of CSDs). In many cases these geographies match; most differences are related to where First Nations Reservations are placed. Statistics Canada splits Reserves across CDs whereas MOHLTC selects one county to place the entire reserve.

In many cases public health units consist of either single or groups of counties or CDs, however, in some cases (marked with an asterisk in Table 1 below) a CD will fall into more than one health unit area. (see map of Ontario Public Health Unit and County Boundaries) For this reason, when
aggregating data which is based on census geography, it is preferable to group CSDs rather than CDs into health units. Some current health units are a result of past amalgamations of health units, these are highlighted in Table 2 below. As of June 2006, there are 36 public health units in
Ontario.

TABLE 1: Public Health Units by Census Division

*Indicates census divisions which fall into more than one health unit area.Table 2: Amalgamated Public Health Units

The highest level of geography in the MOHLTC’s system is the Health Planning Region. The boundaries of these regions differ from those for other Ontario Ministries such as the Ministry of the Environment and the Ministry of Community, Family and Children’s Services. The MOHLTC has seven Health Planning Regions (Central East, Central South, Central West, East, North, South West, and Toronto) which replaced the five previous regions (Central East, Central West, South West, North and East) in 1998. These previous five regions also coincided with the five Health Intelligence Units (HIUs) which were in existence in Ontario between 1996 and March 2005.

Another level of geography used by the MOHLTC was that of the 16 District Health Units (DHCs). The DHCs were disbanded in March 2005.

Local Health Integration Networks (LHINs) were established in 2005. LHINs are non-profit organizations that are designed to plan, coordinate and fund the delivery of health care services across the province. Though the LHIN boundaries do not coordinate well with all existing Public Health Unit boundaries, they do provide another geographic unit for analyzing health data. Table 3 below shows the LHINs by Public Health Unit. (see map of LHIN boundaries http://www.health.gov.on.ca/transformation/lhin/lhinmap_mn.html)

TABLE 3: Local Health Integration Network (LHINs) by Public Health Unit (PHU)

*Indicates public health units which fall into more than one LHIN area.