Municipalities in Ontario

Sparsely populated Northern Ontario mostly lacks local government, instead using provincially-contracted local services boards to provide services. The exception is larger centres, which have unitary authorities. Although Northern Ontario can be divided into districts, these divisions are used only for census purposes.

Unitary authority ("Single-tier") configuration
This style of local government is found in two contexts:
 * The result of a provincially-mandated merger of a county with its constituent municipalities.
 * An independent city, in Southern Ontario formed by leaving the county.

Result of merger

 * County of Brant
 * Chatham-Kent, formerly Kent County (seat in Chatham)
 * Greater Sudbury, formerly the Regional Municipality of Sudbury
 * Haldimand County, formerly half of the Regional Municipality of Haldimand-Norfolk (seat in Cayuga)
 * Hamilton, formerly the Hamilton-Wentworth Regional Municipality
 * Kawartha Lakes, formerly Victoria County (seat in Lindsay)
 * Norfolk County, formerly half of the Regional Municipality of Haldimand-Norfolk (seat in Simcoe)
 * Ottawa, formerly the Regional Municipality of Ottawa-Carleton
 * Prince Edward County (seat in Picton)
 * Toronto, formerly Metropolitan Toronto

Independent cities in Southern Ontario, and their former counties

 * Barrie - Simcoe County
 * Belleville - Hastings County
 * Brantford - County of Brant
 * Brockville - Leeds &amp; Grenville County
 * Gananoque - Leeds &amp; Grenville County
 * Guelph - Wellington County
 * Kingston - Frontenac County
 * London - Middlesex County
 * Orillia - Simcoe County
 * Pembroke - Renfrew County
 * Peterborough - Peterborough County
 * Prescott - Leeds &amp; Grenville County
 * Quinte West - Hastings County
 * Smiths Falls - Lanark County
 * St. Marys - Perth County
 * St. Thomas - Elgin County
 * Stratford - Perth County
 * Windsor - Essex County

Independent cities in Northern Ontario
Algoma District (Sault Ste. Marie)
 * Blind River
 * Bruce Mines
 * Dubreuilville
 * Elliot Lake
 * Hilton Beach
 * Hilton
 * Hornepayne
 * Huron Shores
 * Jocelyn
 * Johnson
 * Laird
 * Macdonald, Meredith and Aberdeen Additional
 * Plummer Additional
 * Prince
 * Sault Ste. Marie
 * Spanish
 * St. Joseph
 * Tarbutt and Tarbutt Additional
 * The North Shore
 * Thessalon
 * Wawa
 * White River

Cochrane District (Cochrane)
 * Black River-Matheson
 * Cochrane
 * Fauquier-Strickland
 * Hearst
 * Iroquois Falls
 * Kapuskasing
 * Mattice-Val Côté
 * Moonbeam
 * Moosonee
 * Opasatika
 * Smooth Rock Falls
 * Timmins
 * Val Rita-Harty

Kenora District (Kenora)
 * Dryden
 * Ear Falls
 * Ignace
 * Kenora
 * Machin
 * Pickle Lake
 * Red Lake
 * Sioux Lookout
 * Sioux Narrows-Nestor Falls

Manitoulin District (Gore Bay)
 * Assiginack
 * Billings
 * Burpee and Mills
 * Central Manitoulin
 * Cockburn Island
 * Gordon/Barrie Island
 * Gore Bay
 * Northeastern Manitoulin and The Islands
 * Tehkummah

Nipissing District (North Bay)
 * Bonfield
 * Calvin
 * Chisholm
 * East Ferris
 * Mattawa
 * Mattawan
 * North Bay
 * Papineau-Cameron
 * South Algonquin
 * Temagami
 * West Nipissing

Parry Sound District (Parry Sound)
 * Armour
 * Burk's Falls
 * Callander
 * Carling
 * Joly
 * Kearney
 * Machar
 * Magnetawan
 * McDougall
 * McKellar
 * McMurrich/Monteith
 * Nipissing
 * Parry Sound
 * Perry
 * Powassan
 * Ryerson
 * Seguin
 * South River
 * Strong
 * Sundridge
 * The Archipelago
 * Whitestone

Rainy River District (Fort Frances)
 * Alberton
 * Atikokan
 * Chapple
 * Dawson
 * Emo
 * Fort Frances
 * La Vallee
 * Lake of the Woods
 * Morley
 * Rainy River

Sudbury District (Espanola)
 * Baldwin
 * Chapleau
 * Espanola
 * French River
 * Killarney
 * Markstay-Warren
 * Nairn and Hyman
 * Sables-Spanish Rivers
 * St. Charles

Thunder Bay District (Thunder Bay)
 * Conmee
 * Dorion
 * Gillies
 * Greenstone
 * Manitouwadge
 * Marathon
 * Neebing
 * Nipigon
 * O'Connor
 * Oliver Paipoonge
 * Red Rock
 * Schreiber
 * Shuniah
 * Terrace Bay
 * Thunder Bay

Timiskaming District (Haileybury)
 * Armstrong
 * Brethour
 * Casey
 * Chamberlain
 * Charlton and Dack
 * Cobalt
 * Coleman
 * Englehart
 * Evanturel
 * Gauthier
 * Harley
 * Harris
 * Hilliard
 * Hudson
 * James
 * Kerns
 * Kirkland Lake
 * Larder Lake
 * Latchford
 * Matachewan
 * McGarry
 * Temiskaming Shores
 * Thornloe

Regional municipalities and constituents
Durham (Whitby)
 * Ajax
 * Brock
 * Clarington
 * Oshawa
 * Pickering
 * Scugog
 * Uxbridge
 * Whitby

Halton (Milton)
 * Burlington
 * Halton Hills
 * Milton
 * Oakville

Muskoka District (Bracebridge)
 * Bracebridge
 * Georgian Bay
 * Gravenhurst
 * Huntsville
 * Lake of Bays
 * Muskoka Lakes

Niagara (Thorold)
 * Fort Erie
 * Grimsby
 * Lincoln
 * Niagara-on-the-Lake
 * Niagara Falls
 * Pelham
 * Port Colborne
 * St. Catharines
 * Thorold
 * Wainfleet
 * Welland
 * West Lincoln

Oxford County (Woodstock)
 * Blandford-Blenheim
 * East Zorra-Tavistock
 * Ingersoll
 * Norwich
 * South-West Oxford
 * Tillsonburg
 * Woodstock
 * Zorra

Peel (Brampton)
 * Brampton
 * Caledon
 * Mississauga

Waterloo (Kitchener)
 * Cambridge
 * Kitchener
 * North Dumfries
 * Waterloo
 * Wellesley
 * Wilmot
 * Woolwich

York (Newmarket)
 * Aurora
 * East Gwillimbury
 * Georgina
 * King
 * Markham
 * Newmarket
 * Richmond Hill
 * Vaughan
 * Whitchurch–Stouffville

Counties and constituents
Bruce County (Walkerton)
 * Arran-Elderslie
 * Brockton
 * Huron-Kinloss
 * Kincardine
 * Northern Bruce Peninsula
 * Saugeen Shores
 * South Bruce Peninsula
 * South Bruce

Dufferin County (Orangeville)
 * Amaranth
 * East Garafraxa
 * East Luther Grand Valley
 * Melancthon
 * Mono
 * Mulmur
 * Orangeville
 * Shelburne

Elgin County (St. Thomas)
 * Aylmer
 * Bayham
 * Central Elgin
 * Dutton/Dunwich
 * Malahide
 * Southwold
 * West Elgin

Essex County (Windsor)
 * Amherstburg
 * Essex
 * Kingsville
 * Lakeshore
 * LaSalle
 * Leamington
 * Pelee
 * Tecumseh

Frontenac County (Kingston)
 * Central Frontenac
 * Frontenac Islands
 * North Frontenac
 * South Frontenac

Grey County (Owen Sound)
 * Chatsworth
 * Georgian Bluffs
 * Grey Highlands
 * Hanover
 * Meaford
 * Owen Sound
 * Southgate
 * The Blue Mountains
 * West Grey

Haliburton County (Minden)
 * Algonquin Highlands
 * Dysart et al.
 * Highlands East
 * Minden Hills

Hastings County (Belleville)
 * Bancroft
 * Carlow/Mayo
 * Centre Hastings
 * Deseronto
 * Faraday
 * Hastings Highlands
 * Limerick
 * Madoc
 * Marmora and Lake
 * Stirling-Rawdon
 * Tudor and Cashel
 * Tweed
 * Tyendinaga
 * Wollaston

Huron County (Goderich)
 * Ashfield–Colborne–Wawanosh
 * Bluewater
 * Central Huron
 * Goderich
 * Howick
 * Huron East
 * Morris-Turnberry
 * North Huron
 * South Huron

Lambton County (Sarnia)
 * Brooke-Alvinston
 * Dawn-Euphemia
 * Enniskillen
 * Lambton Shores
 * Oil Springs
 * Petrolia
 * Plympton–Wyoming
 * Point Edward
 * Sarnia
 * St. Clair
 * Warwick

Lanark County (Perth)
 * Beckwith
 * Carleton Place
 * Drummond/North Elmsley
 * Lanark Highlands
 * Mississippi Mills
 * Montague
 * Perth
 * Tay Valley

Leeds and Grenville United Counties (Brockville)
 * Athens
 * Augusta
 * Edwardsburgh/Cardinal
 * Elizabethtown - Kitley
 * Front of Yonge
 * Leeds &amp; the Thousand Islands
 * Merrickville-Wolford
 * North Grenville
 * Rideau Lakes
 * Westport

Lennox and Addington County (Greater Napanee)
 * Addington Highlands
 * Greater Napanee
 * Loyalist
 * Stone Mills

Middlesex County (London)
 * Adelaide-Metcalfe
 * Lucan-Biddulph
 * Middlesex Centre
 * Newbury
 * North Middlesex
 * Southwest Middlesex
 * Strathroy-Caradoc
 * Thames Centre

Northumberland County (Cobourg)
 * Alnwick/Haldimand
 * Brighton
 * Cobourg
 * Cramahe
 * Hamilton
 * Port Hope
 * Trent Hills

Perth County (Stratford)
 * North Perth
 * Perth East
 * Perth South
 * West Perth

Peterborough County (Peterborough)
 * Asphodel-Norwood
 * Cavan-Monaghan
 * Douro-Dummer
 * Galway-Cavendish and Harvey
 * Havelock-Belmont-Methuen
 * North Kawartha
 * Otonabee-South Monaghan
 * Smith–Ennismore–Lakefield

Prescott and Russell United Counties (L'Orignal)
 * Alfred and Plantagenet
 * Casselman
 * Champlain
 * Clarence-Rockland
 * East Hawkesbury
 * Hawkesbury
 * Russell
 * The Nation

Renfrew County (Pembroke)
 * Admaston/Bromley
 * Arnprior
 * Bonnechere Valley
 * Brudenell, Lyndoch and Raglan
 * Deep River
 * Greater Madawaska
 * Head, Clara and Maria
 * Horton
 * Killaloe, Hagarty and Richards
 * Laurentian Hills
 * Laurentian Valley
 * Madawaska Valley
 * McNab/Braeside
 * North Algona-Wilberforce
 * Petawawa
 * Renfrew
 * Whitewater Region

Simcoe County (Barrie)
 * Adjala–Tosorontio
 * Bradford West Gwillimbury
 * Clearview
 * Collingwood
 * Essa
 * Innisfil
 * Midland
 * New Tecumseth
 * Oro-Medonte
 * Penetanguishene
 * Ramara
 * Severn
 * Springwater
 * Tay
 * Tiny
 * Wasaga Beach

Stormont, Dundas and Glengarry United Counties (Cornwall)
 * North Dundas
 * North Glengarry
 * North Stormont
 * South Dundas
 * South Glengarry
 * South Stormont

Wellington County (Guelph)
 * Centre Wellington
 * Erin
 * Guelph/Eramosa
 * Puslinch
 * Mapleton
 * Minto
 * Wellington North