A
- Amherstburg
- (Hastings County) Astra
- (Grey County) Aberdeen
- (Comtés unis de Prescott et Russell) Aberdeen
- (Lambton County) Aberfeldy
- (Wellington County) Aberfoyle
- (Regional Municipality of Niagara) Abingdon
- (Simcoe County) Achill
- (Hastings County) Actinolite
- (United Counties of Leeds and Grenville) Actons Corners
- (Parry Sound District) Adanac
- (Middlesex County) Adelaide
- (Renfrew County) Admaston
- (Parry Sound District) Ahmic Lake
- (Wellington County) Aikensville
- (Middlesex County) Ailsa Craig
- (Nipissing District) Airy
- (Hastings County) Albert
- (Nipissing District) Alderdale
- (Durham) Aldred's Beach
- (Comtés unis de Prescott et Russell) Alfred
- (Algoma) Algoma Mills
- (Renfrew County) Alice
- (Hastings County) Allan
- (Grey County) Allan Park
- (Renfrew County) Allans Corners
- (Regional Municipality of Niagara) Allen's Corners
- (Simcoe County) Allenwood
- (Simcoe County) Allenwood Beach
- (Haliburton County) Allsaw