Ontario Counties

Under Ontario law, counties regions are considered upper-tier municipalities. In northern Ontario, there are districts that provide no municipal services and all municipalities organized within those districts are single-tier.

• Algoma District County (ON)
• Brant County (ON) - Single-tier municipality
• Bruce County (ON) - Upper-tier municipality
• Chatham-Kent County (ON)
• Cochrane District County (ON)
• Dufferin County (ON) - Upper-tier municipality
• Durham County (ON) - Upper-tier municipality (Region)
• Elgin County (ON) - Upper-tier municipality
• Essex County (ON) - Upper-tier municipality
• Frontenac County (ON) - Upper-tier municipality
• Grey County (ON) - Upper-tier municipality
• Haldimand County (ON)
• Haliburton County (ON) - Upper-tier municipality
• Halton County (ON) - Upper-tier municipality (Region)
• Hamilton County (ON) - Single-tier municipality (there is also a Hamilton Twp within Northumberland County)
• Hastings County (ON) - Upper-tier municipality
• Huron County (ON) - Upper-tier municipality
• Kawartha Lakes County (ON)
• Kenora District County (ON)
• Lambton County (ON) - Upper-tier municipality
• Lanark County (ON) - Upper-tier municipality
• Leeds and Grenville County (ON) - Upper-tier municipality
• Lennox and Addington County (ON) - Upper-tier municipality
• Manitoulin District County (ON)
• Middlesex County (ON) - Upper-tier municipality
• Muskoka District County (ON) - Upper-tier municipality (Region)
• Niagara County (ON) - Upper-tier municipality (Region)
• Nipissing District County (ON)
• Norfolk County (ON)
• Northumberland County (ON) - Upper-tier municipality
• Ottawa County (ON) - Single-tier municipality
• Oxford County (ON) - Upper-tier municipality (Region)
• Parry Sound District County (ON)
• Peel County (ON) - Upper-tier municipality (Region)
• Perth County (ON) - Upper-tier municipality
• Peterborough County (ON) - Upper-tier municipality
• Prescott and Russell, United Counties of - Upper-tier municipality
• Prince Edward County (ON)
• Rainy River District County (ON)
• Renfrew County (ON) - Upper-tier municipality
• Simcoe County (ON) - Upper-tier municipality
• Stormont, Dundas, and Glengarry, United Counties of - Upper-tier municipality
• Sudbury District County (ON)
• Thunder Bay District County (ON)
• Timiskaming District County (ON)
• Toronto County (ON) - Single-tier municipality
• Waterloo County (ON) - Upper-tier municipality (Region)
• Wellington County (ON) - Upper-tier municipality
• York County (ON) - Upper-tier municipality (Region)