| A.Booth and Company |
| A.H. Reginald Buller (1874-1958) |
| Abandoned mines |
| Abbotsford Lumber Company |
| Aberdeen Association |
| Aberdeen, Countess of (Ishbel Marjoribanks) |
| Aberdeen, Lord |
| Abert, James W. |
| Abestos |
| Abidjan |
| Abitibi Power & Paper Company |
| Abitibi Power and Paper (firm) |
| Abitibi-Consolidated |
| Abitibi-Temiscamingue |
| Abitibi-Témiscamingue |
| Abus des drogues |
| Academic |
| Acadia |
| Acadian |
| Acadians |
| Acadie |
| Acadien |
| Acadiens |
| Académie Royale des Sciences |
| Access to the sea |