A
- (Wellington County) Alma
- (Parry Sound District) Alsace
- (Grey County) Alsfeldt
- (Durham) Alsops Beach
- (Ottawa) Alta Vista
- (Lanark County) Althorpe
- (Durham) Altona
- (Grey County) Alvanley
- (Lambton County) Alvinston
- (Dufferin County) Amaranth Station
- (Bruce County) Ambleside
- (Lennox and Addington County) Amherstview
- (Perth County) Amulree
- (Regional Municipality of Niagara) Ancaster
- (Perth County) Anderson
- (Lanark County) Andrewsville
- (United Counties of Leeds and Grenville) Anoma Lea
- (Hastings County) Anson
- (Algoma) Ansonia
- (Peterborough County) Anstruther Lake
- (Cochrane District) Anthony
- (Ottawa) Antrim
- (Middlesex County) Appin
- (Ottawa) Applewood Acres
- (Peterborough County) Apsley
- (Simcoe County) Apto
- (Ottawa) Arbeatha Park
- (Parry Sound District) Ardbeg
- (Frontenac County) Ardendale
- (Simcoe County) Ardmore Beach