Ontario, being the largest Province in Canada, contains many large municipalities, and thus most provide enough geospatial data that they often have their own data portals. Ontario also covers a large geography, so it makes use of a tiered Municipal system in most parts of the province.
This structure affects who provides which datasets, so it is helpful to know this classification, to better understand the coverage of data available. Some datasets exist only at the upper‑tier level, and some exist only at the lower‑tier levels. Then to keep things interesting, you may find that some regions publish data from both levels, and some publish no GIS data, leaving everything to the local municipalities.
Upper‑Tier Municipalities are regional governments or counties that include several local municipalities. These would include regions like Peel, York, Durham, Halton, Waterloo, Niagara, and Counties like Wellington, Oxford, Huron, Bruce, Grey, Perth, etc.
You could think of them as like an “umbrella” level that includes a group of towns/cities, and they typically manage regional based data portals that often include datasets featuring roads, services management, regional planning, and foundational layers like address points, and boundaries.
Lower‑Tier Municipalities are the local municipalities located within an upper‑tier region or county. For example, you would find Markham, Vaughan, and Richmond Hill are lower-tier levels found within the York Region (an upper-tier region). Most rely on the support of upper tier and will provide data through those shared portals; however, some lower-tier municipalities are large enough that they also operate their own open data portals. Here you typically find data related to local streets, zoning area, local parks and services, and sometimes property parcels.
Single‑Tier Municipalities are larger municipalities that do not belong to any upper tier affiliation. These would include large, urbanized areas like Toronto, Ottawa or Hamilton
These structure levels have been included in our list of Ontario data sources table below, as a way to help users know where to look, when searching for data types.
