A
- Aberarder
- Aberfeldy
- Aberfoyle
- Aberfoyle Creek Estates
- Abingdon
- Achill
- Actinolite
- Actons Corners
- Adamsville
- Addison
- Adelaide
- Adelaide Metcalfe
- Adjala-Tosorontio
- Adolphustown
- Agency Indian Reserve No. 30
- Ahmic Harbour
- Ahmic Lake
- Aikensville
- Ailsa Craig
- Airlie
- Akwesasne
- Akwesasne 59
- Albert
- Albuna
- Albury
- Alcona
- Alderslea
- Alexandria
- Algonquin
- Algonquin Highlands
- Allanburg
- Allan Park
- Allenford
- Allens Corners
- Allensville
- Allenwood
- Allenwood Beach
- Alliance
- Allimil
- Allimill
- Allisonville
- Alliston
- Allsaw
- Alma
- Alpine Village
- Alport
- Alsace
- Alsfeldt
- Alvanley
- Alvinston
- Ambassador Beach
- Amberley
- Ambleside
- Ameliasburg
- Amherstburg
- Amherst Pointe
- Amherstview
- Amiens
- Amigari Downs
- Amigo Beach
- Amik/Talisman
- Amulree
- Ancona Point
- Andy's Corners
- Angus
- Annable Settlement
- Annan
- Anoma Lea
- Anstruther Lake
- Anten Mills
- Antioch
- Appin
- Appledore
- Apple Hill
- Apsley
- Apto
- Arbor-Vitae
- Archer
- Ardbeg
- Ardmore Beach
- Ardtrea
- Argyle
- Ariss
- Arkell
- Arkona
- Arkwood
- Arkwright
- Arlington
- Armour
- Armow
- Armstrong Mills
- Arner
- Arnstein
- Arran-Elderslie
- Arranvale
- Arthur
- Arthur's Corners
- Arva
- Ashby Mill
- Ashfield-Colborne-Wawanosh
- Ashworth
- Aspdin
- Asphodel-Norwood
- Assabaska Indian Reserve
- Asselstine
- Assumption
- Athens
- Atherley
- Atherton
- Athlone
- Athol
- Attercliffe
- Attercliffe Station
- Atwood
- Auburn
- Auden Park
- Aughrim
- Augusta
- Avalon Park
- Avening
- Avery Point
- Avon
- Avonbank
- Avondale
- Avonmore
- Avonry
- Avonton
- Axe Lake
- Aylesworth
- Aylmer
- Ayr
- Ayton