William Grant (also known as William Grant “of Three Rivers”) was born in 1743 in Kirkmichael, Scotland, and died in 1810 near William Henry (Sorel), Lower Canada. He was the son of John Grant and Genevieve Forbes and came from a large family that had many members active in the fur trade during the early decades of British rule. In 1787, Grant married Marguerite Fafard in Trois-Rivières, and they had five children. Grant moved to Montreal in 1767 and worked as a merchant in the fur trade, pursuing this career for nearly twenty years. He worked with associates in the region southwest of Michilimackinac (Mackinaw City, Michigan) and in the vicinity of Lake Superior and Lake Nipigon. Grant engaged in wholesale and retail trading of products imported from Great Britain, conducting his business primarily in Trois-Rivières where he lived with his family. In 1791, Grant joined Étienne-Charles Campion, a Michilimackinac trader, and Samuel Gerrard, a Montreal merchant, in establishing the firm of Grant, Campion and Company, which played a large role in the trade southwest of the Great Lakes and the Timiskaming region. While active in this firm, he supplied James Mackenzie, one of his business partners, with imported merchandise for the local market. Soon after, Grant chose a new associate named Claude Laframboise and remained in partnership with him until 1800, doing business under the name of William Grant and Company in Trois-Rivières and Grant and Laframboise in Montreal. In 1801, he settled in Nicolet with his family. In 1792, Grant was appointed justice of the peace for the Trois-Rivières district.