| Enumerated Area | pre1851 | 1851 | 1861 | 1871 | 1881 | 1891 | 1901 | 1911 |
| Aberdeen Twp | ALG | ALG | ||||||
| Abinger | LnA | LnA | LnA | LnA | LnA | LnA | ||
| Actinolite Village | HAS | HAS | ||||||
| Acton | WGT | |||||||
| Acton Village | HTN | HTN | HTN | HTN | ||||
| Addison Village | LEE | |||||||
| Adelaide Twp | MID | MID | MID | MID | MID | MID | MID | MID |
| Adelaide Village | MID | |||||||
| Adjala Twp | MS | SIM | SIM | SIM | SIM | SIM | SIM | |
| Admaston Twp | REN | REN | REN | REN | REN | REN | REN | |
| Adolphustown Twp | LnA | LnA | LnA | LnA | LnA | LnA | LnA | |
| Agincourt Village | YOR | |||||||
| Ahmic Harbor | PSD | |||||||
| Ahmic Lake | MUS | |||||||
| Ailsa Craig Village | MID | MID | MID | MID | ||||
| Aird Island | NIP | ALG | ||||||
| Airy Twp | HAS | HAS | NIP | NIP | ||||
| Albemarle Twp | BRU | BRU | BRU | BRU | BRU | BRU | ||
| Alberton Twp | ALG | |||||||
| Albion Twp | PEE | PEE | PEE | PEE | PEE | PEE | PEE | |
| Alcon | TBRR | |||||||
| Aldborough Twp | ELG | ELG | ELG | ELG | ELG | ELG | ELG | ELG |
| Alexandria Village | GLE | GLE | GLE | |||||
| Alfred Twp | PRE | PRE | PRE | PRE | PRE | PRE | PRE | PRE |
| Algoma Mills | ALG | ALG | ALG | |||||
| Algoma Mills Twp | NIP | |||||||
| Algoma Twp | ALG | |||||||
| Algona North Twp | REN | REN | REN | REN | ||||
| Algona South Twp | REN | REN | REN | |||||
| Algona Twp | REN | REN | ||||||
| Alice Twp | REN | REN | REN | REN | REN | REN | ||
| Allan Twp | ALG | ALG | ALG | ALG | ||||
| Allandale Twp | SIM | |||||||
| Allen | NIP | |||||||
| Allenford | BRU | |||||||
| Alliston Village | SIM | SIM | SIM | SIM | ||||
| Alma Village | BRU | |||||||
| Alma Village | WGT | |||||||
| Almonte Town | LNK | LNK | LNK | LNK | LNK | |||
| Alnwick Indian Reserve | ONT | |||||||
| Alnwick Twp | NUL | NUL | NUL | NUL | NUL | NUL | NUL | NUL |
| Alvinston Village | LAM | LAM | LAM | LAM | ||||
| Amabel Twp | BRU | BRU | BRU | BRU | BRU | BRU | ||
| Amaranth Twp | WGT | WGT | WGT | WGT | WGT | WGT | DUF | |
| Amberley Village | BRU | |||||||
| Ameliasburg Twp | PED | PED | PED | PED | PED | PED | PED | |
| Amherst Island | LnA | LnA | LnA | LnA | LnA | LnA | LnA | |
| Amherstburg Town | ESS | ESS | ESS | ESS | ESS | ESS | ||
| Amyott | ALG | |||||||
| Ancaster Twp | WTW | WTW | WTW | WTW | BRA | BRA | WTW | |
| Anderdon Twp | ESS | ESS | ESS | ESS | ESS | ESS | ||
| Anderson's Island | ALG | |||||||
| Andrew Bay | TBRR | |||||||
| Andrewsville Village | LNK | |||||||
| Anglesea Twp | LnA | LnA | LnA | LnA | LnA | LnA | ||
| Anglin | NIP | NIP | ||||||
| Angus Village | SIM | |||||||
| Annan Village | GRY | GRY | ||||||
| Anson Twp | VIC | VIC | VIC | VIC | VIC | VIC | ||
| Anstruther Twp | PET | PET | PET | PET | PET | |||
| Antoine | NIP | |||||||
| Antrim Village | CAR | |||||||
| Appin Village | MID | |||||||
| Appleby | NIP | |||||||
| Appleby Twp | NIP | NIP | NIP | |||||
| Appleton Village | LNK | |||||||
| Apsley Village | PET | |||||||
| Arden Village | FRO | |||||||
| Ardoch Village | FRO | |||||||
| Ariss | WGT | |||||||
| Arkell | WGT | |||||||
| Arkona Village | LAM | LAM | LAM | LAM | ||||
| Armour Twp | MUS | MUS | MUS | PSD | ||||
| Armstrong Twp | NIP | |||||||
| Arnprior Town | REN | REN | REN | REN | REN | REN | ||
| Arran Twp | BRU | BRU | BRU | BRU | BRU | BRU | BRU | |
| Artemesia Twp | GRY | GRY | GRY | GRY | GRY | GRY | GRY | |
| Arthur Twp | WGT | WGT | WGT | WGT | WGT | WGT | WGT | |
| Arthur Village | WGT | WGT | WGT | WGT | ||||
| Asburn | ONT | |||||||
| Ash Rapids Twp | ALG | |||||||
| Ashburnham Village | PET | PET | PET | PET | PET | |||
| Ashby Twp | LnA | LnA | LnA | LnA | LnA | |||
| Ashfield Twp | HUR | HUR | HUR | HUR | HUR | HUR | HUR | HUR |
| Asphodel Twp | PET | PET | PET | PET | PET | PET | PET | |
| Assabasca | TBRR | |||||||
| Assiginack Twp | ALG | ALG | ALG | ALG | ||||
| Astrom Bay | ALG | |||||||
| Athens Village | LEE | LEE | LEE | |||||
| Atherley Village | ONT | |||||||
| Athol Twp | MS | PED | PED | PED | PED | PED | PED | |
| Atikokan | ALG | TBRR | ||||||
| Attercliffe Station | HLD | |||||||
| Attercliffe Village | LIN | |||||||
| Atwood Twp | ALG | TBRR | ||||||
| Aubrey Twp | ALG | TBRR | ||||||
| Audley | ONT | |||||||
| Augusta Twp | GVL | GVL | GVL | GVL | GVL | GVL | GVL | GVL |
| Aumick Lake | PSD | |||||||
| Aurora | NIP | |||||||
| Aurora Town | YOR | YOR | YOR | YOR | YOR | |||
| Avenge | ALG | ALG | ||||||
| Avening Village | SIM | |||||||
| Avon Village | MID | |||||||
| Avon Village | ELG | |||||||
| Avonmore Village | STO | STO | ||||||
| Awrey | NIP | NIP | NIP | |||||
| Aylesworth Twp | ALG | TBRR | ||||||
| Aylmer | NIP | |||||||
| Aylmer Town | ELG | ELG | ELG | ELG | ||||
| Ayr Village | WAT | WAT | WAT | |||||
| Ayton Village | GRY |