Henry Oldham Mackenzie was born on November 21, 1825, in Terrebonne, Quebec, a son of Roderick Mackenzie (1761–1844) and Marie Louise Rachel Chaboillez (1786-1853). He died on May 30, 1879.

Frederick Mackenzie was born on April 10, 1841, in Montreal, Quebec, the son of John Gordon Mackenzie (1796–1881), a wealthy dry goods merchant.

He was a lawyer and politician. He was educated at McGill University and was called to the bar in 1862. He was a captain in the militia and served during the Fenian raids (1866, 1870-1871). He was a secretary for the Church of England in Quebec and Montreal. Mackenzie represented Montreal West in the House of Commons of Canada from 1874 to 1875 as a Liberal member.

He died on July 2, 1889, in Boston, Massachusetts, and is buried in Montreal, Quebec.

Charles Mackenzie was born in Scotland in 1774. In 1803 he entered the service of the North West Co. In 1804, he was a clerk on the Assiniboine. Mackenzie made four trading expeditions to the Missouri Indians in the years 1804 to 1806. His account of the Missouris was published by L.R. Masson in his Bourgeois de la Compagnie du Nord-Ouest (1889). He spent most of the rest of his service in the region of Rainy Lake and Albany where he was transferred in 1807. He was a clerk for the Hudson's Bay Co. from 1821 until he retired in 1854. He died at the Red River Settlement in 1855.

Alexander MacKenzie was born on October 8, 1805, in Montreal and died on May 10, 1862, in Terrebonne, Quebec. He was a son of Roderick Mackenzie (1761-1844) and Marie Louise Rachel Chaboillez (1786-1853). Mackenzie married Marie-Louise Trottier Desrivières Beaubien in 1833. He was an officer in the British Army and a partner in the North West Company.

Scottish explorer Mackenzie is best known for his east-west overland crossing of Canada to the Pacific 1793. He was born in Stornoway in the Scottish Outer Hebrides. He sailed for North America in 1774 and was sent to school in Montréal. By 1779, he was worked as an apprentice for Finlay, Gregory & Co., afterwards Gregory, McLeod and Co., and which later merged with the North West company in 1787. He was sent to Detroit in 1784 and to the West in 1785. When the firm was absorbed in the North West Co. in 1787, Mackenzie joined the North West as a partner. He traveled to Athabasca in 1788, leaving on an expedition to try find a northwest passage to the Pacific, reaching the Arctic Ocean. The river Mackenzie that he traveled in now named after him. Mackenzie made an expedition to the Arctic Ocean from Fort Chipewyan in 1789 along the river which now bears his name. His significant expedition in 1792 took him across Canada to the Pacific, using recent advancements in the study of longitude that he had learned in London. In 1793 he journeyed to the Pacific Ocean. In 1790 he severed his connection with the North West Co. and returned to England, where he published his Voyages in 1801 and was knighted in 1802. He returned to Canada in 1802 to become a leading partner in the XY Company. In 1805 Mackenzie was elected to the Legislative Assembly of Lower Canada from Huntingdon County. In 1812, Mackenzie returned to Scotland and married Geddes Mackenzie. He died in Scotland in 1820.

John MacKellar (d. 1854) was a British Admiral who succeeded Robert Murray as prison agent at the Office for Prisoners of War located in Halifax, Nova Scotia. He held the post from 1804 until approximately 1810. He was the eldest son of General MacKellar, who was employed as chief engineer under General Wolfe.