John Sandfield Macdonald | |
|---|---|
 Macdonald, c. 1870 | |
| 1st Premier of Ontario | |
| In office July 16, 1867 – December 20, 1871 | |
| Monarch | Victoria |
| Lieutenant Governor | Henry William Stisted William Pearce Howland |
| Preceded by | Position established |
| Succeeded by | Edward Blake |
| Joint Premier of the Province of Canada | |
| In office May 24, 1862 – March 29, 1864 | |
| Governor General | Viscount Monck |
| Preceded by | John A. Macdonald |
| Succeeded by | John A. Macdonald |
| Member of the Legislative Assembly of the Province of Canada for Glengarry | |
| In office 1841–1844 | |
| Preceded by | Position established |
| Personal details | |
| Born | December 12, 1812 St. Raphael West, Glengarry County, Upper Canada |
| Died | June 1, 1872 (aged 59) Cornwall, Ontario, Canada |
| Resting place | St. Andrews Cemetery, South Stormont, Ontario |
| Political party | Liberal-Conservative |
| Spouse | Marie Christine Waggaman |
| Relatives | Donald Alexander Macdonald and Alexander Francis Macdonald |
| Signature |  |
| Military service | |
| Allegiance | Upper Canada |
| Branch/service | Canadian militia |
| Years of service | 1830s–1852 |
| Rank | Lieutenant Lieutenant-Colonel |
| Unit | Queen's Light Infantry Militia (Toronto) Glengarry Militia Regiment of the Eastern District |
| Commands | 4th Battalion, Glengarry Militia |
John Sandfield Macdonald, QC (December 12, 1812 – June 1, 1872) was the joint premier of the Province of Canada from 1862 to 1864. He was also the first premier of Ontario from 1867 to 1871, one of the four founding provinces created at Confederation in 1867. He served as both premier and attorney general of Ontario from July 16, 1867, to December 20, 1871.
He was referred to by his middle name, Sandfield, and often signed his correspondence and documents as J. Sandfield Macdonald.