Below is a list organized by Regions, Counties, Districts and Single-Tiers.
A regional government is a federation of the local, lower tier municipalities within its boundaries. Regions are referred to as "upper tier" municipalities and provide services such as: arterial roads; transit; policing; sewer and water systems; waste disposal; region-wide land use planning and development; as well as health and social services. Depending on its size and its history, a local municipality may be called a city, a town, or a township or a village. They are also referred to as "lower tier" municipalities when there is another level of municipal government like a county or region involved in providing services to residents.
A county government is a federation of the local municipalities within its boundaries. Counties are referred to as "upper tier" municipalities. Counties exist only in southern Ontario. Local municipalities (cities, towns, villages, townships) within counties provide the majority of municipal services to their residents. The services provided by county governments are usually limited to arterial roads, health and social services and county land use planning.
Areas may use the term district but these are territorial boundaries that do not serve any municipal government purpose. Only the District Municipality of Muskoka provides services on a regional-scale.
Single-tier municipalities exist across Ontario. They include separated municipalities that are geographically located within a county (see County list) but are not part of the county for the municipal purposes. Single-tier municipalities also include all northern municipalities (see Northern list) where there is no upper-tier governance at the District level. Finally single-tier municipalities include those former county or regional municipalities that have recently been amalgamated into single-tier municipality. Single-tier municipalities have responsibilities for all local services to their residents.|